Sunday, March 27, 2011
6-4 Hyperbolas
Hyperbolas are in the form x^2/a^2 –y^2/b^2 or –x^2/a^2 + y^2/b^2.
Part of the Equation:
1. Major axis – variable with larger denominator (non-negative)
2. Minor axis –variable with smaller denominator
3. Length of major –2 square root of non-negative denominator
4. Length of minor –2 square root of smaller denominator
5. Vertex – square root of non-negative denominator
If x is major: (_,0) and (-_, 0)
If y is major: (0,_) and (0, -_)
6. Other intercepts – square root of smaller denominator … ( , ) opposite of vertex
7. Focus – focus squared = larger denominator + smaller denominator
If x is major: (focus, 0)
If y is major: (0, focus)
8.Asymptotes –
If x is major: y = +/- b/ax
If y is major: y = +/- a/bx
Examples:
X^2?25-Y^2/100=1
1. x
2. y
3. 10
4. 20
5. (5,0)(-5,0)
6. (0,10)(0,-10)
7. (5square root of 5,0)( -5square root of 5,0)
8. y= + and – 2x
Basically if you know your rules and stuff it easy and it the same thing as 6-3 rules but couple new steps to 6-4 that all.
6-4
In the form x2/a – y2/ = 1 or –x2/a2 + y2/b2/
Parts of the equation
-Major axis : variable with larger denominator
-Minor axis: variable with smaller denominator
-Length of major: 2 square root non negative denominator
-Length of minor: 2 square root smaller denominator
-Vertex: square root non negative denominator if x is major (_,0 )and (-_,0); if y is major (0,_) and (0,-_)
-Other intercept: smaller denominator ( , ) Opposite of vertex
- Focus: focus2 = larger denominator and smaller denominator if x is major (focus,0) if y is major (0,focus)
-Asymtoles: y = +/-b/ax if x is major, y = +/-a/bx if y is major
solving the system
Honestly, I tried a bunch of different times to work a problem to put on here but all of the different numbers I tried just would not work out. They all came out with big fractions that I just don’t know how to complete. Im sorry I couldn’t figure it out but it is a pretty simple process whenever you already have a problem given to you. (This blog is over 150 words though)
Saturday, March 26, 2011
6-4
Section 6-4 dealt with hyperbolas. Hyperbolas are in the form x^2/a^2 –y^2/b^2 or –x^2/a^2 + y^2/b^2.
Parts of the equation are similar to the ellipse.
1. Major axis – variable with larger denominator (non-negative)
2. Minor axis – variable with smaller denominator
3. Length of major – 2*square root of non-neg denominator
4. Length of minor – 2*square root of smaller denominator
5. Vertex – square root of non-neg denominator
If x is major: (_,0) and (-_, 0)
If y is major: (0,_) and (0, -_)
6. Other intercepts – square root of smaller denominator … ( , ) opposite of vertex
7. Focus – focus squared = larger denominator + smaller denominator
If x is major: (focus, 0)
If y is major: (0, focus)
**SOMETHING DIFFERENT: Asymptotes –
If x is major: y = +/- b/ax
If y is major: y = +/- a/bx
EXAMPLE 1: x^2/9 – y^2/16 Find all parts.
1. x (since 16 is negative)
2. y
3. 2*square root of 9 = 6
4. 2*square root of 16 = 8
5. square root of 9 = (3, 0) and (-3,0)
6. square root of 16 = (0,4) and (0,-4)
7. 9 + 16 = 25
focus = 5
8. y = +/- 4/3x
Hope everyone has a fun, memorable weekend!
Sunday, March 20, 2011
a matrices review..
Prom is next saturday:D but im sure you guys already know :) im kinda excited about it too. But anyways,I cant seem to find my chapter six notes so ill blog about something we did a while back. Matrices, yayyy. Just like every other area of advanced math, matrices are tedious.
Here are the matrices rule:
When adding matrices, they must be of the same dimensions. The same goes for subtracting
Ex. A 4x3 matrices can only be added to a 4x3 matrices
When multiplying matrices, you can only multiply matrices that have the same columns and rows.
Ex. 3x3* 1x2 the column of the first are equal to the rows of the second.
You cannot technically divide a matrices, to "divide" a matrices, you simply multiply by the inverse..
finding the inverse.
0 1
1 0 = 0-1=-1 = 1/-1* 0 1
1 0 = 0 -1
-1 0
Zomg
So this week in Advanced Math we started chapter six, but we skipped 6-1 because B-Rob said it was dumb. So, one thing we learned was section 2 which is all about connics and the equation of a circle.
First, you must remember how to complete a square. To complete a square, you must put it in standard form. Then, get rid of the coefficient of x^2 or y^2. Next, divide the middle term by 2 and square it. Add the number to both sides. Then factor in (x )^2 form.
The mid point formula is also needed for this. As a remindered, it's (Xv1+ Xv2)/2, (Yv1+Yv2)/2.
The distance formula is used as well when given a center point and an outside point.
The equation of a circle is (x-h)^2 +(y-k)^2 = r^2 where (h,k) is the center.
Example of how to make an equation--
C=(4,3) r=2
(x-4)^2 + (y-3)^2 = 4
Example of finding coordinates of the point where the lines intersect--
y= 2x-2 and circle x^2 +y^2=25
By calculator:
plug in y=2x-2 and y= + or - square root (25-x)^2
Then hit graph
Then hit second trace
The click a point on the top circle
Then a point on the line
Then guess where about they intersect.
Answer-
(3,4)
Chapter 6
Ellipses have many parts.
Major axis- Found by whcih axis has the larger denominator
Minor axis- Found by which axis has amaller denominator
Length of the major axis- Found with the equation. 2xSquare root(larger denominator)
Length of the minor axis-.............................................................(Smaller denominator)
Intercepts, major and minor- Is the square root(Larger denominator) or (smaller denominator). Takes place of corresponding variable, depending on which is major, the other variable is 0
Focus- I think its Larger Denominator=Smaller Denominator+Focus squared
Major axis – the variable with the larger denominator
Minor axis – the variable with the smaller denominator
Length of the major axis – 2 square root of the larger denominator
Length of the minor axis – 2 square root of the smaller denominator
Vertex – square root of the larger denominator if x is major (_,0) and (-_,0) and if y is major (0,_) (0,_)
Other intercept – square root of smaller denominator ( ,) Opposite of vertex
Focus – Smaller denominator = larger denominator, focus2 is x is major (0, focus) (focus,0)
Example 1:
x2/9 + y2/36 = 1
1) Major axis - y
2) Minor axis – x
3) Length of Major – 2 square root 36 = 12
4) Length of Minor – 2 square root 9 = 6
5) Vertex – (0, 6) (0, -6)
6) Other intercept – (3,0) (-3,0)
7) Focus – 9 = 36 –f2 =-27 = square root 27 (0, square root 27) (0,-square root 27)
6-2
CONICS
*equation of a circle
(x-h)^2 + (y-k)^2 = r^2
**where (h,k) is the center.
D=square root of (y2-y1)^2 + (x2-x1)^2 = r
-get rid of coefficient of x^2 or y^2
-divide middle term by 2 and square it.
-add to both sides
-factor to (x)^2
EXAMPLE:
(x-7)^2 + (y+2)^2=25
CENTER: (7,-2)
RADIUS: square root of 25 = 5
6-3
ELLIPSES
* x^2/a + y^2/b = 1
PARTS OF THE EQUATION:
major axis-variable with larger denominator
minor axis-variable with smaller denominator
length of major-2 square root of larger denominator
length of minor-2 square root of smaller denominator
vertex-if x is major ( ,0) & ( ,0)
if y if major (0, ) & (0, )
other- opp. of vertex ( , )
focus- smaller denom. = larger denom. - focus^2
if x is major (0, focus)
if y is major (focus, 0)
6-3
Part of the Equations:
Major axis
Minor axis
length of major
length of minor
Vertex
Other Int
Focus
Examples: Find all the parts of X^2/4+y^2/25=1
1. Major axis= y
2. Minor axis=z
3 Length of major=10
4. length of minor=4
5. vertex= (0,5)(0,-5)
6. Other Int=(2,0)(-2,0)
7. focus=( 0,square root of 21)(0,-square root of 21)
Basically if you know all your steps and procedure you will not have any problem at this section and this will be a breeze for you to.
6-3
chapter 6
1. Tell the major axis
2. Tell the minor axis.
3. Length of major
4. Length of minor
5. Vertex
6. Other intercepts
7. Focus
All of these things are pretty easy to find.
Ex: x^2/25 + y^2/9 = 1
^^ all of them must equal 1.
1. Major axis- x because the number on the bottom is bigger
2. Minor axis-y
3. Length of major – 10 (2 times the square root)
4. Length of minor- 6
5. Vertex – (5,0) (-5,0) (square root of the major axis. The number goes in the x spot since it is larger.
6. Other intercepts- (0,3)(0,-3)
7. focus- 4 ( smaller denominator = larger denominator – f^2)
6-3
**This is the form of an ellipse equation: x^2/a + y^2/b
Step or parts of ellipse equation:
1. Major axis is the variable with larger denominator.
2. Minor axis is the variable with smaller denominator.
3. Length of major is 2 times the square root of larger denominator
4. Length of minor is 2 times the square root of smaller denominator.
5. Vertex is square root of larger denominator.
If x is major you should use this (_,0) and (-_, 0).
If y is major you should use this (0,_) and (0, -_).
6. Other intercepts is square root of smaller denominator ( , ) opposite of vertex.
7. Focus is the smaller denominator = the larger denominator – the focus squared.
If x is major you should use this (0, focus).
If y is major you should use this (focus, 0).
EXAMPLE 1: Find all the parts of x^2/4 + y^2/16.
1. y
2. x
3. 8
4. 4
5. (0,4) (0,-4)
6. (2,0) (-2,0) 6. 7 = 16 – focus squared
focus = (0,3) (0,-3)
This is how you find the equation thingy or whatever to an ellipse.
6-3
This past week we learned about conics, ellipses, and hyperbolas.
Ellipses are in the form: x^2/a + y^2/b
Parts of the equation:
1. Major axis – variable with larger denominator
2. Minor axis – variable with smaller denominator
3. Length of major – 2*square root of larger denominator
4. Length of minor – 2*square root of smaller denominator
5. Vertex – square root of larger denominator
If x is major: (_,0) and (-_, 0)
If y is major: (0,_) and (0, -_)
6. Other intercepts – square root of smaller denominator … ( , ) opposite of vertex
7. Focus – smaller denominator = larger denominator – focus squared
If x is major: (0, focus)
If y is major: (focus, 0)
EXAMPLE 1: Find all the parts of x^2/9 + y^2/25.
1. y
2. x
3. 2 * the square root of 25 = 10
4. 2 * the square root of 9 = 6
5. Since y is the major, (0,5) and (0,-5)
6. (3,0) and (-3,0) 7. 9 = 25 – focus squared
focus = +/- 4 therefore, (0,4) and (0,-4) is your focus.
Sunday, March 13, 2011
5-5
Chapter 5-Section 5
Chapter 5, section 5 includes three formulas you must know. They are listed below:
The first formula involves:
A(t) = A (1 + r)t
A- is the orignal amount
r- is the rate
t- is amount of time
The second formula involves:
A(t) =A bt/k
A- is the original amount
b- whether you half, triple, or quaterly
t- is the time
k-the time it takes to get to b
** used with doubling
The thrid formula involves:
P(t) = P er/t
** used with continuosly
EXAMPLE:
You must choose which formula you use when given a problem. Example:You invest 3,000 at 16% intrest compounded continuously. How much money will you have after 2 years?
Plug into your calculator P = 3000e^(.16)(2) = $7.351.02
Exponents
Ration exponents:
Formulas:
A(t)=A0b^(t/k)
-A0 is starting point
-b is halfing, doubling, ect
-t is time and k is time it takes to get to b
Examples:
3rd root of square root of x= x^1/3
(16/100)^1/2= square root of 16/square root of 100 which can be simplified to 2/5
27^2x=3^2
(3^3)^2x=3^2
3^6x=3^2
6x=2
x=1/3
5-7
This holiday was very much needed! I am going to hate having to go back to school, but hey only two more weeks until Easter! I hope everyone had a good Mardi Gras! Before we left for break we closed out Chapter 5 and took our exam. This part of trig is getting kind of tricky, but if you follow the basic steps it can be easy.
Chapter 5- Section 7
There are two methods we learned in chapter 5, section 7; we were taught how to solve for a variable as an exoponent and also learned to change the base of a log.
** Take the log of both sides when solving for a variable as an exponent. After that is done take the exponent and bring it to the front of the equation.
EXAMPLE 1:
Solve 10^x=8
1. Take the log of both the left and right side.
log 10^x = log 8
2. Now, bring the exponent to the front .x log 10 = log 8
3. Solve for the variable, in this case x.X = log 8/log 10
EXAMPLE 2:
Solve 3^x=81
1. Take the log of both sides.log 3^x = log 81
2. Bring the exponent to the front.x log 3 = log 81
3.Solve for x.x = log 81/log 3D).
Your final answer is 4.
**Change of base formula:
log b^a:log x^a/ log x^b
EXAMPLE 1:
Change log 3^9 to base 4.
1.Using the formula, you get log 4^7/log 4^9
Mardi Gras
like: log(little 8)64=2, thats easy
Something like this: log(little8)x^(4700+10t)-log(little x)10+58, tends to get kind of difficult.
chapter 5
Okay, so for my second blog of the break, I am pretty much going to do the same thing that I did in my previous blog. Like I said, chapter 5 did give me some trouble and I am definitely not looking forward to going back to school tomorrow. I enjoyed my break a lot and I’m sure the rest of you have too. Unfortunately it had to end. Alright back to math.
*I won’t be able to get the final answer because I’m dumb and left my calculator somewhere*
There are 3 formulas that we were given that we needed to know the difference between them and when to use each.
1. A(t) = a0 b^t/k * this formula is used when doubling, halfing, tripling, etc..
2. A(t) = a0 ( 1 + r)^t *used with regular problems with no “special” words
3. P(t) = p0 e^rt * use this one when you see words such as continuously or compounding
Since I don’t have my calculator and they are all worked the same way, I’ll just do one example.
Ex: Suppose a radioactive isotope decays so that the radioactivity present decreases by 23% per day. If 56kg are present now, find the amount that will be present 6 days from noow.
Since there are no key words, you will use formula number 2.
A(t) = 56 ( 1 + .23 ) ^6
You just plug that straight into the calculator to get your answer.
chapter 5
Before the mardi gras break we learned chapter 5 and took our 3rd nine weeks exam on it. That was probably the hardest exam I took out of all my classes. However, the problems really are very simple to do, they can just get a little confusing at times. Some of them hardly require much work either. I’ll just show a few random problems of things we learned.
The first example is going to be about exponential equations:
The formula for this is: f( x ) = a x b^x
Find the equation of the exponential if f(0) = 5 and f(2) = 20
F(x) = a x b^x
F(x) = 5 x b^x
20 = 5 x b^ 2
B^2 = 4
B = +/- 2
Other things that are very simple is changing a base given logb^a, you will end up with an answer in the term log x^a/ log x^b
Example: change log3 7 to base 5
Log5 7/log5 3
Soooo I’m back again writing my second blog of the break. Once again I will stay I am very bummed that break it over already. I have been super busy all week and it just flew by. I really wanted to aleks extra credit but I did not have any time this week so that sucks. Anyway I’m going to do so more examples from chapter 5 which has to do with like logs and formulas and other stuff. It’s easy enough I guess but I guess we will have to wait for exam grades to be posted to see how well I know my stuff.
Chapter 5 involves three main formulas:
Formula 1 : A(t) = A (1 + r)t
Formula 2: A(t) =A bt/k
Formula 3: P(t) = P er/t
You must choose which formula you use when given a problem.
Example:
You invest 2,000 at 6% intrest compounded continuously. How much money will you have after 3 years?
Plug into your calculator P = 2000e^(.06)(3) = $6371.02
Hey everyone I hope everyone had a great break, I know I did but I am super bummed it’s over already. It seems like it flew by! Anyway the last week we were in school we learned chapter 5 and our exam we took on Friday was on chapter 5. I hope I did okay enough on it to pass (: Now let’s see if I remember how to do any of this stuff cause it’s been awhile…Rational Exponents look easy enough so let’s get started, here ya go!
Exponents that involve roots:
Example 1:
3 square root of 4 = 41/3
Example 2:
(9/25)1/2 = 91/2/251/2 = square root 9/ square root 25 = 3/5
Solve :
Example 3:
49 4x = 78
(72)4x = 78 Bases must be the same
78x = 78
8x = 8 Set exponents equal
X = 1
Okay I think this blog screwed up the way everything looks but your smart people and can figure it out for yourselves.
Friday, March 11, 2011
guess what everyone?! rascal flatts concert is sundayyy! which is why im posting early and not waiting last minute :)
i hope everyone had a great mardi gras holiday like i did although i was busy everyday!
FORMULAS:
logb MN=logbM + logbN
logb M/N=logbM - logbN (anything in the bottom is NEGATIVE)
logM^k=KlogM
to set 2 log equal set the insides equal.
**right side is expanded
**left side is condensed
EXPAND:
logbMN^2
logbM+logbN^2
=logbM+2logbN
CONDENSE:
log 45-2log3
log45-log3^2
log45-log9
log45/9
=5
byeeeeee peeps :)
so last week we completed chapter 5 and took our super hard exam. anddddd we did aleks.
chapter 5 was pretty decent, logs are not THATTTTTTT bad but i guess i didnt know them as good as i thought.
writing in exponentials.
EXAMPLE.
log4 64=3
4^3=64.
^^that's your answer. soooooo easy.
there's some with word problems but im not very good at making up word problems much less making them with numbers that will actually give me a normal answer :(
FORMULAS:
a(t)=a0(1+r)^t
a0----your starting point.
r----your decimal number
t----time ( must match rate )
(used with percents)
a(t)=a0 b ^t/k
(used when doubling, halfing, tripling)
p(t)=P0e^rt
p0---starting point
r---rate as decimal
t---time
Keywords (continuously, compounding)
5-6
5-6
Properties of Logs:
1. Log b MN = log b M + log b N
2. Log b M/N = log b M – log b N
3. Log b M^k = k log b M
(RIGHT SIDE IS CONDENSED, LEFT SIDE IS EXPANDED).
EXAMPLE 1: Condense log M – 3 log N
A). First, check to see which property it’s following. With the – sign, we automatically know the
answer will be in fraction form, property #2.
B). Also, the second half (3 log N) is property #3. Changing that, we get log N^3
C). Now we can continue..
log M/log N^3
EXAMPLE 2: Condense log 8 + log 5 – log 4
A). Simply the 3 parts to get 2 so we can condense. Since log 8 and log 5 are the same, multiply 8 and 5.
B). Now we have log 40 – log 4.
C). Having the – sign, we know we’re going to follow property #2.
log 40/log 4
D). Your answer is 10.
EXAMPLE 3: Expand log b MN^2
A). Following property #1, we get log b M + log b N^2
B). Now bring all exponents to the front to get your final answer.
log b M + 2 log b N
5-7
5-7
When solving for a variable as an exponent, you take the log of both sides. Then you bring the exponent to the front and solve.
EXAMPLE 1: Solve 10^x=4
A). Take the log of both the left and right side.
log 10^x = log 4
B). Now, bring the exponent to the front.
x log 10 = log 4
C). Solve for the variable, in this case x.
X = log 4/log 10
EXAMPLE 2: Solve 3^x=81
A). Take the log of both sides.
log 3^x = log 81
B). Bring the exponent to the front.
x log 3 = log 81
C). Solve for x.
x = log 81/log 3
D). Your final answer is 4.
To change a base given log b^a:
log x^a/ log x^b
EXAMPLE 1: Change log 3^7 to base 4.
A). Using the formula, you get
log 4^7/log 4^3
Sunday, March 6, 2011
5-7
To solve for a variable as a exponent you take the log of both sides, bring the exponents to the front and solve.
- to change a base given log( base is b)^a
Log( base x)^a/log( base x)^b is where x is the base you want
Examples:
Change log (base 5)^8 to base 2
Log(base 2)8/ log (base 2) 5
Solve 3^x=81
Log 3^x=log 81
X log 3= log 81
X=log 81/log 3 = 4
If you know all your steps and the procedure of doing this you will not get stuck on this and it will be really easy for you.
Sunday, February 27, 2011
Rational Exponents
Formulas:
A(t)=A0b^(t/k)
-A0 is starting point
-b is halfing, doubling, ect
-t is time and k is time it takes to get to b
Examples:
3rd root of square root of x= x^1/3
(16/100)^1/2= square root of 16/square root of 100 which can be simplified to 2/5
27^2x=3^2
(3^3)^2x=3^2
3^6x=3^2
6x=2
x=1/3
Basically if you know your rules and the formula this section will be easy..
chapter 5
The first formula we did was the easiest for me. It is:
A(t) = Ao (1 + r)^t
This formula is used with word problems when given a percent, time and rate.
Ao= your starting number
R= the rate
T= time
After you read the problem, you plug in the numbers to the formula, type it in your calculator, and it gives you the answer. (percents must be changed to decimals)
Ex: Suppose you have $1,000 dollars invested at a 7% interest rate. How much money will you have after 2 years?
A(t) = $1,000 (1 + .07)^2
^^ plug that into your calculator and you get $1144.90 as your answer.
Chapter 5
Solve the following problems:
Example 1:
7-2 = 1/49
Example 2:
(-7)-2 = -1/49
Example 3:
When given a chart you must pick one of the following formulas:
Read the problem, plug in the numbers, and then into your calculator and get an answer.
A(t) = Ao (1+r)2
A(t) = Ao b t/k
P(t) = Po ert
Rational Exponents
FORMULAS:
A(t)=A0b^(t/k)
A0 is starting point
b is halfing, doubling, ect
t is time and k is time it takes to get to b
Exponents that involve roots.
EXAMPLE:
5th root of (3)^3
3^3/5
(4/16)^1/2
2/4 which is equal to 1/2
*This is the easiest way to explain rational exponents.
EXAMPLE:
6square root of x^3--------x^3/6
FORMULAS:
a(t)=a0(1+r)^t
0---is your starting point
r---is your decimal
t---is your time
*when given a word problems you can easily plug it into the formula. once you have it plugged into your formula you can then put it in your calculator to get your final answer. It's really simple so i hope we have a good bit of these on our 9 weeks exam friday :)
i've still been trying to do aleks but it keeps kicking me off my computer. i am learning with using aleks.
Exponents
Almost forgot about this! This week in Advanced Math we learned about exponents and formulas involving percent, rate, and time. Section 5-4 involved one formula – P(t)=Pe^r*t
P – starting amount
e – on calculator (e is approximately 2.7)
r – rate as a decimal
t – time
EXAMPLE 1: Suppose $2,000 is invested at 5% interest compounded continuously. How much money do you have after 3 years?
A). Using the formula, plug in the information given.
P=2,000(starting amount)e^(0.5*3)
B). By plugging all of that into your calculator, you get $8963.38 as your final answer.
EXAMPLE 2: Which has a larger value? e^square root of 3 or 3^e
A). The answer to this problem can be achieved by plugging the two into your calculator.
B). e^square root of 3 = 5.65 and 3^e = 19.81
C). Therefore, the first one has a larger value.
This is a little short but my computer is installing new updates and it’s counting down to shutdown!
Sunday, February 20, 2011
blog.blog.blog.
well this week everyone has really been busy with the carnival ball and what not. But despite all the hectic over that i must admit that the week was pretty productive for my advanced math and physics classes anyway..but anywho we learned a lot vectors again. When we were'nt learnning about vectors, we were working on our ALEKS which is gonna be done pretty soon.
we learned how to tell if vectors were parallel or perpendicular..you can do this by doing dot product. if the answer is equal to zero, then vectors are perpendicular.
ex. ( 2,3) (0,0)
(2*0)+(0*3)
=0+0
=0
therefore, the two vectors are perpendicular :)
in order for two vectors to be parallel they must be proportional. Here is an example of two vectors that are proportional, and parallel.
ex. x(1,2) y(2,3) z(3,4)
2/1=3/2=4/3
2=3/2=4/3
so noo, these vectors are not parallel which is too bad :(
Examples:
Matrices:
2[ 1 2 4] + 3{3 2 5]
{2 4 8} + { 9 6 15}= [ 11 10 23}
Named the matrices
{ 1 3 4 5}
{ 2 4 8 9} = 2x4
find AB
A(1 4 8) B(5 4 7)= (4, 0, -1)
point 8,-2, 3 and 4, 0, 7
Find center = (6,-1,5)
Radius square root (4-8)^2+(0+2)^2(7-3)^2=16+4+16 = square root of 36= 6
Equation = (x-6)^2+(y+1)^2+(2-5)^2=9^2
Formulas you need to know for this section are below:
AB = square root (x2-x1)2 + (y2-y1)2 + (z2+z1)2
Midpoint = (x1 + x2/2) (y1 + y2/2) (z1 + z2/2)
Equation of a Sphere = (x-xo)2 + (y-yo)2 + (z-zo)2 = r2
Vector equation (x,y,z) = (xo, yo, zo) + t(a,b,c)
Vector addition, magnitude, dot product, etc.are just a little different but follow the same formulas as earlier sections. They just have an extra variable in the formula unlike before.
Example
Find the center and radius Point A (8,4,2) Point B (2, 8,6)
Center – 9 + 7/2 = 8, 5 + 3/2 = 4, 7 + 5/2 = 6 (8,4,6)
Radius – square root (7 - 9)2 + (3 - 5)2 + (5 – 7)2 = 6+ 6 + 6= square root 16/2 = square root 8
Find the equation
(x – 8)2 + (y – 4)2 + (z – 6)2 = 8
glad ive said that now on to some math.
Finding whether something is parallel or perpendicular is my favorite.
EXAMPLE:
j=(3,4,2) k=(15,8,4)
PARALLEL:
15/3=5
8/4=2
4/2=2
PERPENDICULAR:
3(15)+4(8)-2(4)
**in order for it to be perpendicular it must equal 0.
****therefore its neither.
The AB thing is easy too.
A(2,3,1) B(4,2,6)
4-2=2
2-3=-1
6-1=5
*your answer is (2,-1,5)
my computer keeps freezing so im going to post now.
Random example of matrices:
Solve the matrices:
2 [ 3 4 5 ] = [ 6 8 10 ]
[ 7 8 ] + [ 9 10 ] = [ 16 18 ]
Name the matrices:
[ 2 4 5 6 9 ] is a 1 x 5
[ 9 10 15 ]
[ 1 12 20 ] is a 2 x 3
Vectors
DIRECTIONS:
1. You should make sure you have a vector, u and v are always vectors.
2. Then you should add x1 to x2 and you will come out with a new vector.
3. You should do the same thing for subtraction just simply subtract the vectors.
EXAMPLES:
u=<4,5> v=<3,4>
Addition:
Find u+v
<4,5>+<3,4>
answer:<7,9>
Subtraction:
Find u-v
<4,5>-<3,4>
answer:<1,1>
*This is the easiest thing you will learn to do with vectors from my point of view.
*Just remember add the x's and add the y's and the same rules apply for subtraction.
3x3
Example 1: (I won't have the brackets around them because I don't know how to do that)
6 2 3
1 2 4
0 1 1
1. you want to pick the row with the smallest numbers and cross it out.
2. cross out the first column, so you are left with:
0 * 2 3
2 4
3. Now cross out the second column, and so on ( alternate the sigsn of subtraction and addition.)
0 * 2 3 + 1 * 6 3 - 1 * 6 2
2 4 1 4 1 2
4. Now just multiply your matrices.
8-5= 3 *0 = 0
24-3 = 21 * 1 = 21
12-2= 10 * 1 = 10
0 +21 -10= 11
11 is your answer!
Saturday, February 19, 2011
The formula to find midpoint is (x1+x2/2, y1+y2/2, z1+z2/2)
IABI = square root (x2-x1)squared +(y2-y1)squared + (z2-z1)squared
Vector equation = (x, y, z) = (xo, yo, zo) + t(a, b, c) *a, b, and c is your vector
EXAMPLE 1: A sphere has points (6, 2, 3) and (2, 2, 7). Find the center and radius.
A). Use the midpoint formula first.
(6+2/2, 2+2/2, 3+7/2) = (4, 2, 5)
B). Now use the IABI formula.
Square root (2-6)squared + (2-2)squared + (7-3)squared = 0
C). The answer you get there is your diameter.
D. Now plug the answer you got from step A into the vector equation formula.
(x-4)squared + (y-2)squared + (z-5)squared = 0 (radius squared)
EXAMPE 2: Find the vector and parametric equations of the line containing (1, 3, 5) and (2, 8, 9)
A). Use your vector equation formula.
(x, y, z) = (1, 3, 5) + t(1, 5, 4)
*(1, 5, 4) is found by subtracting x2-x1, y2-y1, and z2-z1
B). x = 1 + t, y = 3 + 5t, and z = 5 + 4t
Alrighttttttttttttttt, hope everyone has a great weekend and good luck to everyone at Carnival Ball :)
Sunday, February 13, 2011
Inverse for a 3x3
First, you are going to have to pick a row with the lowest numbers in them, then delete the row in column that they are in leaving you with a 2x2 finding the determine of that then multiplying the outside number by the determinate roatating signs postive and negative, starting with positive, and then add all the determinates up.
EXAMPLE:
1. [1 2 2
0 0 1
1 3 0]
0[2 2 0[1 2 1[0 0
3 0] - 1 0]+ 1 3]
0-0+0= 0
so your answer for this one happens to be 0.
3-D
|AB| = square root (x2-x1)2 + (y2-y1)2 + (z2+z1)2
Midpoint = (x1 + x2/2) (y1 + y2/2) (z1 + z2/2)
Equation of a Sphere = (x-xo)2 + (y-yo)2 + (z-zo)2 = r2
Vector equation (x,y,z) = (xo, yo, zo) + t(a,b,c)
Vector addition, magnitude, dot product, etc. all follow the same formula with extra variable.
Example: point 8,-2, 3 and 4, 0, 7
Find center = (6,-1,5)
Radius square root (4-8)^2+(0+2)^2(7-3)^2=16+4+16 = square root of 36= 6
Equation = (x-6)^2+(y+1)^2+(2-5)^2=9^2
Basically if you know your formulas you will do pretty good at this section if not you will do horrible at this section.
Formulas you need to know for this section are below:
AB = square root (x2-x1)2 + (y2-y1)2 + (z2+z1)2
Midpoint = (x1 + x2/2) (y1 + y2/2) (z1 + z2/2)
Equation of a Sphere = (x-xo)2 + (y-yo)2 + (z-zo)2 = r2
Vector equation (x,y,z) = (xo, yo, zo) + t(a,b,c)
Vector addition, magnitude, dot product, etc.are just a little different but follow the same formulas as earlier sections. They just have an extra variable in the formula unlike before.
Example
Find the center and radius Point A (8,4,2) Point B (2, 8,6)
Center – 9 + 7/2 = 8, 5 + 3/2 = 4, 7 + 5/2 = 6 (8,4,6)
Radius – square root (7 - 9)2 + (3 - 5)2 + (5 – 7)2 = 6+ 6 + 6= square root 16/2 = square root 8
Find the equation
(x – 8)2 + (y – 4)2 + (z – 6)2 = 8
Math 3 dimensions
The formula used is- square root (x2-x1)^2+(y2-y1)^2+(z2-z1)^2
Ex: Find |AB| for the points ( 2,3,2) (6, 7, 4)
Square root (6-2) ^2 + (7 – 3) ^2 + (4 – 2)^2
16 + 16 +4 = 36
Square root 36 = 4; |AB| = 6
3D
For magnitude: |AB| = squareroot (x2 – x1)^2 + (y2 – y1)^2 + (z2 + z1)^2
Ex: Find |AB| for the points ( 2, 3), (3, 7), (1, 0)
Square root (3-2) ^2 + (7 – 3) ^2 + (0 – 1)^2
1 + 16 -1 = 16
Square root 16 = 4; |AB| = 4
Ex2: Find |AB| for the points (3, 6) , (3, 0 ) , ( 4, 7)
Square root ( 6 – 3 ) ^2 + ( 0 - 3 ) ^2 + ( 7 – 4 ) ^2
9 -9 + 9 = 9
Square root 9 = 3; |AB| = 3
|AB| = square root (x2-x1)2 + (y2-y1)2 + (z2+z1)2
Midpoint = (x1 + x2/2) (y1 + y2/2) (z1 + z2/2)
Equation of a Sphere = (x-xo)2 + (y-yo)2 + (z-zo)2 = r2
Vector equation (x,y,z) = (xo, yo, zo) + t(a,b,c)
Vector addition, magnitude, dot product, etc. all follow the same formula with extra variable.
Example
Find the center and radius Point A (9,5,7) Point B (7, 3,5)
Center – 9 + 7/2 = 8, 5 + 3/2 = 4, 7 + 5/2 = 6 (8,4,6)
Radius – square root (7 - 9)2 + (3 - 5)2 + (5 – 7)2 = 4 + 4 + 4 = square root 12/2 = square root 3
Find the equation
(x – 8)2 + (y – 4)2 + (z – 6)2 = 3
Friday, February 11, 2011
12-1
Section 12-1 was about vectors. Vectors represent motion and have a magnitude and direction. To add vectors, you add head to tail. To add vectors algebraically, you add components. To find the magnitude of a vector, you use the formula square root of x^2 + y^2. When given two points, such as A and B, and asked to find the vector, you use the formula (x2 – x1, y2 – y1).
Having these few little notes, let’s try an example.
EXAMPLE 1: Given A(6,4) and B(8, 9), find the vector AB.
A). According to the notes above, we’re going to use the last formula.
B). First, subtract the x’s (8-6) = 2
C). Now, subtract the y’s (9-4) = 5
D). Your vector is (2,5)
EXAMPLE 2: Find the magnitude of EXAMPLE 1’S answer. **MAGNITUDE HAS TO BE WITH A VECTOR!
A). Since we’re finding the magnitude, use the square root formula.
B). square root 2^2+5^2 = square root 4 + 25
C). Your magnitude is square root 29
Sunday, February 6, 2011
Advanced Math
- Vectors represent motion
- Vectors have a magnitude and a direction
- To add vectors you add head to tail.
- The triangle formed by the vectors give the resultant vector
- To add vectors algebraically you add components
Chapter 12
vector- is a line that represents motion
- line has a magnitude and a direction, which are the points that are given.
- ( x is the head and y is the tail )
- when is given, it is not asking for an absolute value like usual. that symbol means find the magnitude.
When working with a vector, it usually ask for 3 things.
Example:
Find 4t
- That is telling you to take the vector that it gives you and draw it four times connecting in a straight line.
- If it asks you to find –t, you draw the vector facing the opposite direction.
- Lastly, if it wants you to find t + q, you connect the two vectors together, usually creating an angle.
..... Vectors?
Vectors represent motion. They have a magnitude and direction. They are written with a --> over the two given points.
To add vectors, you must add head to tail. The triangle formed by the vectors give the resultant vector. This basically means that the imaginary line you get when you have
^ \ is the answer.
/ v
To add vectors algebraically, you have to add the components. To do that use this formula: (x (subscript 2)-x (subscript 1), y(subscript 2) - y(subscript 1))
-->
Example-- Find AB A(4,2) B(9,-1)
(9-4, -1-2)
=(5,-3)
To find the magnitude, plug the answer you get from the algebraic vector into this formula: square root(x^2 + y^2). Magnitude is shown as | |
-->
Example-- Find the Magnitude of AB
Square root(5^2 + -3^2)
Square root(25+9)
=Square root(34)
chapter 12
12-1 was pretty easy because all there really was for us to do was connect the vectors, add on to them, or flip them around. A vector is a line that represents motion. The line has a magnitude and a direction, which are the points that are given. ( x is the head and y is the tail ) also, when | | is given, it is not asking for an absolute value like usual. | | that symbol means find the magnitude.
As for the vectors, there are 3 things that it usually asks:
For example: Find 4t
That is telling you to take the vector that it gives you and draw it four times connecting in a straight line.
If it asks you to find –t, you draw the vector facing the opposite direction.
Lastly, if it wants you to find t + q, you connect the two vectors together, usually creating an angle.
I think we should continue to go to the library sometimes to do aleks. I find its really helpful and not as boring as doing work out of the book. Sorry this was such a short blog.
Math
vectors represent motion
they have a magnitude and direction.
to add vectors you add head to tail.
the triangle formed by the vectors is your result.
to add vectors algebraically you add the components.
12-1
VECTORS-represent motion
they have a magnitude and direction.
-to add vectors you add head to tail.
-the triangle formed by the vectors is your result.
-to add vectors algebraically you add the components.
12-2
-to find the magnitude
**square root of x^2+y^2
-scalar multiplication puts a scalar times each component.
-you are given 2 points (A&B)
**A&B=(x2-x1;y2-y1)
^^^^remember this from algebra 2!
*it's hard to do examples for 12-1 since they are graphs drawn.
Now im going to spread my love for aleks.com
it is a whole lot easier than doing 2 blogs per week.
im learning from the stupid mistakes i usually do.
its fun?
*i think as a class we all enjoy it. (especially when we do that in class)
byeeeeeeeeeeeeeeee.
14-3
1. First you are going to want to switch the first number of the matrix with the fourth number.
2. Then make the second and third numbers opposite of their sign.
3. Then cross multiply your origional matrix and find the determinate.
4. Take your determinate and multiply it by your second matrix.
EXAMPLE:
1. [2 3
1 4]
[4 -3
-1 2]
(4x2-1x3)= 5
1/5[4 -3
-1 2]
[4/5 -3/5
-1/5 2/5] This is your answer.
This is the easiest way to do this just follow the steps and you should be fine.
12-1,12-2
Vectors-represent motion and it has a magnitude and a direction.
*to add vectors you add head to tail.
the triangle formed by the vectors give the resultant vector.
another thing is to add vector algebraically you add components.
-to find the magnitude
square root of x^2+y^2 magnitude is done as |->|
Ex: A(4,2) B(9,-1) find on top of AB is ->
on top of AB ->(9-4,-1-2)=(5,-3)is on top of AB ->
find the magnitude of on top of AB ->
square root of 5^2+-3^2= square root of 34
Ex: find |on top of AB ->| if A(1,3) B(2,4)
on top of AB -> = 2-1,4-3= (1,1)
|on top of AB ->| Square root of 1^2+1^2= square root of 2.
If you know all your rules and stuff sections 12-1 and 12-2 will be easy for u.
This week in advanced math we took our test on Wednesday instead of Tuesday because we got out of school early due to the weather. The test was super easy so hopefully I got a good grade. Since we took the test on Wednesday we had to double up on learning sections in chapter 12. Sections 12-1 and 12-2 are on vectors. Vectors represent motion. They have a magnitude and a direction.
To add vectors you add the head and the tail. To add vectors algebracically you add the components.
The triangle formed by the vectors give the resultant vector.
To find the magnitude square root x2 + y2 magnitude is done as | -> |
Scalar multiplication puts a scalar times each component.
Given 2 points A and B
->
AB = (x2 – x1 y2 –y1)
Geometric Representation
Find c + d
Connect the head of C to the tail of D.
Find 2s
Connect the head of S to another tail of S.
Find –p
Reverse the p and draw it in the opposite direction.
Saturday, February 5, 2011
14-3
This week we finished Chapter 14 and tested on it. Along with that we continued to work on Aleks and even started Chapter 12 which had to do with vectors. I’m going to explain the concept of finding an inverse in a matrix.
EXAMPLE 1: Given A= [4 3 find its inverse.
2 6]
A). To find an inverse, flip the 1st number on the top row and the 2nd on the bottom (4 and 6) and make the 2nd number on the first row and 1st on the second row negative (-3 and -2).
B). Your new matrix should look like this [6 -3
-2 4]
C). Now cross multiply your original matrix and subtract (4 x 6 – 2 x 3) = 18
D). Mutiply your new matrix by the determinant, which is 1/18.
E). Your answer is [1/3 -1/6
-1/9 2/9]
I know this is a little short but I've been doing Aleks all morning and I'm really frustrated :/ sorry!
Sunday, January 30, 2011
aleks.com
Im just going to do a few examples because im not sure how to explain this concept to well.
Example:
-2= 7x-9/6- 8x+5/7
First we are going to examine the problem and determine the least common demominator.
The least common denominator is 42.
Multiply 42 by each segment of the problem.
(42)-2= 42(7x-9/6-8x+5/7)
(42)-2+ 42(7x-9/6)-42(8x+5/7)
Now divide into the LCD.
-84= 7(7x-9)-6(8x+5)
-84= 49x-63-48x-30
-84=x-93
Now solve for x and
answer is.... x=9
Matrices are AWESOME
Matrices
Well helloo :) my weekend has been going well so far in case you all were wondering. But anyways, this past week we learned about Matrices and we also began the aleks program on the computer. Other than that we pretty much reviewed because we had already learned about matrices in algebra 2. Matrices are pretty simple to work or solve but they are a bit tedious.
There are some rules for matrices:
When adding matrices, they must be of the same dimensions. The same goes for subtracting matrices.
Ex. A 2x3 matrices can only be added to a 2x3 matrices
When multiplying matrices, you can only multiply matrices that have the same colomns and rows.
Ex. 2x3* 3x1 the colomn of the first are equal to the rows of the second.
You cannot technically divide a matrices, to "divide" a matrices, you simply multiply by the inverse..
Ex. inverse
0 1
1 0 = 0-1=-1 = 1/-1* 0 1
1 0 = 0 -1
-1 0
ADDITION:
[2 6]+[5 4]=[7 10]
SUBTRACTION:
[9 2]-[7 1]=[2 1]
MULTIPLICATION:
5[2 4]=[10 20]
So i'm really tired and I probably shouldn't have waited until the last minute to do my blog but oooops. I guess it will just have to be a short one but next week i'll make it longer :)
14-1
This week in advanced math we started chapter 14. Chapter 14 is all about matrices. Matrices are super easy stuff we learned in algebra 2. We finished up our chapter 4 test on Monday and took a quiz either Tuesday or Thursday on matrices but I can’t remember which day. We also started with this new online math website that is kinda like skills tutor. It’s pretty cool I guess, helped me remember some stuff I forgot from algebra 2. Anyway let’s do some super easy problems on matrices.
Examples:
5 [3 6] = [15 30]
[9 10] [45 50]
*this is supposed to be a 2x2 but idk how to do big brackets so all my examples will look pretty
wack so deal with it.
[1 3] + [2 4] = [3 7]
[5 7] [6 8] [11 15]
Name the matrice
[5 6 7]
[4 1 -3]
[3 -1 -4]
3x3
Matrices
ADD:
1. You are going to add the first number in the first matrix to the first number in the second matrix.. you do this for the second, third, forth, and so on.. This rule applies the same for subtracting.
Example:
[1 2 [1 2 [2 4
3 4] + 3 4] = 6 8]
This is as easy as it gets.
2. Subtracting- do the same as adding but you subtract!
Example:
[1 2 [1 2 [0 0
3 4]- 3 4] = 0 0]
This is also as easy as it gets.
3. Transpose- when transposing you just make the row a column.
Example:
[1 2 3 4
5 6 7 8
9 9 9 9]
now transpose it.
[1 5 9
2 6 9
3 7 9
4 8 9]
** This are the easiest possible ways to add subtract and transpose matrices.
I hope you all got the hang of it, if not too bad cause you will officially be called an idiot.
Matrices
Row and column (row go across and column go up and down)
Examples:
1.
-3{1 4} = {3 12 }
9 6 27 18
2.
-{ 1 1 1] determine row x column= 4x3
1 1 1
0 0 0
2 2 2
3.
A={ 2 6}
8 22 a find a^t
9 16
B. A^t= {2 6}
8 22
9 16
C. { 1 2 }{ 2 4}
4 6 0 1
2x2 2x2
Middle two are the same with you do now
{ 2+0 4+2}
8+0 16+6 ={ 2 6}
8 22
{ 1 2} + {2 0} ={ 3 2}
4 6 5 2 9 8
Basically if u remember everything from last year in algebra 2 it is the same thing and all this is review from last year just know your rule about matrices and you will be fine. Btw my brackets sucked I tried my best making it but oh well hope u like it.
Saturday, January 29, 2011
♥ Marjorie Ann Flanagan St. Martin ♥
Gram was the classiest, sweetest, most wonderful woman to walk this earth. While I miss her dearly and mourn over her loss, I think of how great her life was and how she'll be with her husband again. I think of how happy she must be because there is no doubt about her being in heaven. I love my grandma so much. It's hard to believe she's gone.
Rest In Peace Marjorie Ann Flanagan St. Martin. <3
Matrices
The basic part is finding out how big your matrices is: rows x colums
(rows go across and columns are up and down)
Ex 1: [ 2 4 6]
This matrix is a 1x3
To add matrices is very simple. You just add the corresponding numbers.
Ex 2: [ 4 2 4] + [ 7 3 6] = [ 11 5 10]
Super easy and subtraction is done the same way.
Ex 3: [ 8 3 2] – [ 5 4 1] = [ 3 -1 1]
Sorry all of my rows were 1, but I have no clue how else to do it!
Matrices!
We started Chapter 14 this week and it’s all about MATRICES! I’m not really sure how I’m going to type them out so bare with me. You can add and subtract matrices but they have to be the same dimensions. Another thing we learned was how to multiply them. When doing so, you have to have the same number of columns in the 1st one and rows in the 2nd one. We also learned how to find its inverse.
Rows – go across
Columns – up and down
Adding and subtracting matrices is simple..
EXAMPLE 1: [-5 0 + [6 -3
4 1] 2 3]
A). To add matrices, we add the corresponding members. Subtraction is done in the same way.
B). (-5+6) (0-3)
(4+2) (1+3)
C). [1 -3
6 4]
D). Your new matrix is a 2 x 2.
EXAMPLE 2: 3[-3 0
4 5]
A). Multiply each number of the matrix by 3, easy.
B). [-9 0
12 15]
When adding, subtracting, and multiplying matrices be careful of negatives! This blog is nasty looking because of those stupid brackets :/
Sunday, January 23, 2011
4-5
Horizontal line test- similar to the vertical line test only if it passes then there is an inverse that is a function
Sidenote-for our book they will say there isn’t an inverse if it fails
To find an inverse:
-Switch x & y
- solve for y
To check if something is an inverse:
F(g(x))=x
&
g(f(x))=x
-f^-1= inverse notation
Examples:
Prove f(x)=x+3 f^-1(x)=-x-3 are inverse
F(f^-1(X))=x-3+3=x
F^-1(f(X))
(x+3)-3=x
yes it is an inverse.
Y=square root of x-3
x=square root of y-3
square both side you get y-3=x^2
y^-1=x^2+3
it is an inverse because it passes the horizontal line test.
Basically if you know all these formulas and stuff section 4-5 will be easy for you.
Inverses Chapter 4
How to do a horizontal line test: 1.draw horizontal lines across the graph.
2. if it doesn't touch more than one point you can find the inverse.
* Note that in college we will be taught differently and they'll show you a way to find the inverse even if it fails the test.
To show something is an inverse be sure to put the -1 exponent after the y once you have solved the equation.
Example:Find the inverse for y = x -9
You graph this equation, and do the horizontal line test, and it does pass.
1. Switch the x and y. x= y-9
2. Solve for y. y = x + 9
3. Y^-1 = x + 9
Chapter 4
- When you multiply a variable by a number less than 1 it makes the graph shorter and fatter.
- When you multiply a variable by a number bigger than 1 it makes it skinnier and longer.
ALMOST 17 BABY!!!!!!!
You may use these steps to perform the process.
x-axis. Step1. Make all y's in the equation negative.
Step2. Simplify the equation. If the equation is the same then it is symmetrical.
y-axis. Step1. Make all x's in the equation negative.
Step2."......"
origin. Step1. Make both the y and x's negative.
Step2. "......"
y=x Step1. Switch the x and ys
Step2. solve for y
Step3. If equations are equal than it is symmetrical.
This week in advanced math we reviewed for a chapter 4 test. We took a took quizzes on Tuesday and Thursday but the quiz on Tuesday didn’t count. Thank you Mrs. Robinson! We took part of the test Friday and we will take the other test on Monday. Section five of chapter four is on inverses. Here is a few notes of inverses:
Horizontal Line Test – similar to the vertical line test only if it passes then there is an inverse that is a function.
To find an inverse – 1. Switch x and y 2. Solve for y
To check if something is an inverse f(g(x)) = x and g(f(x))
f-1 – inverse notation
Side note – In our textbooks it says if there isn’t an inverse if it fails.
Example:
y = x – 7
x = y – 7
y-1 = x + 7
When you draw the graph it passes the horizontal line test.
Chapter 4
Chapter 4
First: You should graph the equation and make sure it passes the horizontal line test.
(this is so you do not waste time finding an inverse of something that isn't mathematically possible.)
Next: If an inverse, you should switch the x and y and solve for y.
**HINTS:
*If it is x^2 it wont have an inverse because it will be a parabola. (no inverse)
*If it is x it will be a straight line (has an inverse)
* If it is x^3 it will make this weird curve line thingy (has an inverse)
EXAMPLE:
1. y=x^2+4
answer: no inverse (this is a parabola)
2. y=x-4
x=y-4
y^1=x+4 is your answer
I hope that I explained this well and if you think I didn't then you are wrong because I did. Thanks for taking up 5 minutes of my time for 5 extra points. :)
4-5
To find an inverse you have to use the horizontal line test. This is like the vertical line test, but it's horizontal. If it passes without touching two points on the graph then there is an inverse that is a function.
This brings us to the first step - drawing the graph. Since I don't have a fancy laptop, I can't draw a graph. But, here are some hints to see if it will pass the test. If it has an x^2, it will not pass the test because x^2 makes a parabola. An x makes a straight kinda slanted line.
After you graph, to find an inverse switch x and y. Then solve for y.
For example, y = x + 3
First, graph the equation.
By using the horizontal line test, you know that there is an inverse.
Now, switch the x and y.
x = y + 3
And now, solve for y.
y^-1 = x - 3
Place -1 above y to show that it is the inverse.
INVERSES:
****FIRST THING YOU MUST DO IS GRAPH!
*use the horizontal line test to see if it is an inverse. If it only goes through the line once it is an inverse. if it goes through the line more than once it isnt an inverse.
**switch x and y.
*solve for y.
I left my notes at home so im doing this off the top of my head. I hope this stuff is right. And leaving my notebook at home does not help the fact that we have the other part of the chapter test tomorrow :(
I really do not want to go to school tomorrow. Ive been doing schoolwork allllllllll day and i dont think i will ever finish. It makes me really sad that this is what school has done to me. Free time? what is that? All it does is stress me out!
4-5
The horizontal line test is where you draw horizontal lines across a graph. If it does NOT touch more than one point, then it is an inverse. According to the book, if it does not pass this test, then an inverse does not exist. We did learn though that in college, we will be told something different. Also, when you find the inverse, you put an exponent of -1 after the y to show that it is an inverse.
Once you passed the horizontal line test, you can get to working the problem:
Example:
Find the inverse for y = x -9
You graph this equation, and do the horizontal line test, and it does pass.
1. Switch the x and y. x= y-9
2. Solve for y. y = x + 9
3. Y^-1 = x + 9
4-5
1.Draw or sketch the graph
- x^2= parabola
-x= a line
-x^3 = this line..
-sqrt x=that thing..
- ab. value = "v"
* if the graph passes the horoizontal line test, it has an inverse.
2. next you switch the x's and the y's
3. Solve for y
ex.
f(x)=x^2+3x
1.has no inverse because it does not pass the horizontal line test.
ex. y=5x+3
1. passes the horizontal line test
2.x=5y+3
x-3=5y
y(-1)=1/5x-3/5 <---inverse
ex. y=l3xl -6
1. does not pass horizontal line test
Friday, January 21, 2011
4-5
Inverses
Section 4-5 was about finding inverses. To find an inverse you have to use the horizontal line test. This is similar to the vertical line test. If it passes without touching two points then there is an inverse that is a function. That is the first step - drawing the graph.
After that, to find an inverse:
1. Switch x and y.
2. Solve for y.
To check if something is an inverse:
f(g(x)) = x and g(f(x)) = x
EXAMPLE 1: y = x + 4
A). First, graph the equation.
B). By using the horizontal line test, we know that there is an inverse.
C). Now, switch the x and y.
D). x = y + 4 and solve for y.
E). y^-1 = x - 4
* Place -1 above y to show that it is the inverse.
EXAMPLE 2: Prove that f(x) = x - 2 and f^-1(x) = x + 2 are inverses.
A). f(f^-1(x)) = (x + 2) - 2
= x
B). f^-1(f(x)) = ( x - 2) + 2
= x
C). This proves that these are inverses.
Tuesday, January 18, 2011
Week 3 Blog Prompt
Monday, January 17, 2011
Chapter 4
Sunday, January 16, 2011
blogg..
Ex.
x^5+3x-2
first, we figure out whether the equation is a polynomial, an absolute value, a fraction, or a square root. Because the equation does not have a variable in the denominator it therefore is a polynomial.
the domain of a polynomial is always (-infinity, infinity) <-- you have to pay attention to the parenthesis also. Parenthesis only go with infinities and fractions.
The Domain of example one is (-infinity, infinity)
the range is also (-infinity, infinity)
when the exponent of the polynomial ( the greater one) is even the range is (-infinity, infinity) it it is even, then it would be the [number, then infinity)
ex.2 l-4xl +3
the domain of an absolute value is (-infinity, infinity)
the range is the [vertical shift, infinity)
4-3
Check to see if:
X - axis – 1) Plug in (-y)
2) Simplify and solve for y
3) If equations are equal then it has symmetry about x.
Y – axis – 1) Plug in (-x)
2) “ “
3) “ “ y – axis
Origin – 1) Plug in (-x) and (-y)
2) “ “
3) “ “ origin
Y = X – 1) Switch x and y
2) Solve for y
3) “ “ y = x
To graph these types of equations you will do 1 of 3 things:
A) Sketch – f(x) Reflect the x-axis
B) Sketch – f(-x) Reflect the y-axis
C) Sketch - |f(x)| Flip above the axis
Tired
4-3
x axis: plug in (-y), simplify( solve for y), if the equation are = then it has symmetry a/b x.
If it gives you a graph and tells you to sketch -f(x), you take the graph and draw everything on the x axis on the opposite side.
y axis: plug in (-x),simplify (solve for x), If equations are equal then it has symmetry on the y axis.
If it tells you to sketch f(-x) then you take everything on one side of the y axis and draw it to the other.
|f(x)|, flip above axis
1. plug in (-x) & (-y)
2. simplify
If it tells you to sketch |f(x)| then everything on the lower half of the axis, you draw onto the top half.
y=x is also a inverse.
Ms.Robinson this is all i can explain lmao this section is soo confusing that is why i did it to understand it more.
Blah
Anyway, this week was fairly simple in Advanced Math. This section had to do with notation. There are four formulas to find notation: sum, difference, product, and quotient of functions.
1. Sum of f and g: (f+g)(x) = f(x) + g(x)
2. Difference of f and g: (f-g)(x) = f(x) – g(x)
3. Product of f and g: (f * g) g)(x) = f(x) * g(x)
4. Quotient of f and g: (f/g)(x) = f(x)/g(x), provided g(x) not equaled to 0
All this is basically saying is that in the problems that follow, plug everything in the parenthesis of f or g into the equation where there is a variable
For example,
f(3)= 7x= 21
You'd then plug 3 in where there's a x.
7 * 3 = 21
Ta da
For another example
g(4)= 5-x= 9
Then you plug in 4 for the x.
5 - 4 = 9
4-3
Pretty much everything except for 4-2 that we have learned this week has to do with drawing graphs, and since I already did a blog on that and I obviously can't draw any graphs on here, I'll just explain how to work some problems from section 4-3. This section was all about symmetry. Some problems gave you a graph and you had to either sketch:
-f(x), reflect the x axis
1. plug in (-y)
2. simplify (solve for y)
3. if eqations are equal then it has symmetry about x.
* If it gives you a graph and tells you to sketch -f(x), you take the graph and draw everything on the x axis on the opposite side.
f(-x), reflect the y axis
1. plug in (-x)
2. simplify (solve for x)
3. If equations are equal then it has ymmetry on the y axis.
* If it tells you to sketch f(-x) then you take everything on one side of the y axis and draw it to the other.
|f(x)|, flip above axis
1. plug in (-x) & (-y)
2. simplify
* If it tells you to sketch |f(x)| then everything on the lower half of the axis, you draw onto the top half.
Sorry this was confusing, but it is hard to explain it without having some graphs as examples.
Friday, January 14, 2011
4-2 was notation:
1. sum of f and g=(f+g)(x)=f(x)+g(x)
2. difference of f and g=(f-g)(x)=f(x)-g(x)
3. product of f and g=(f x g)(x)=f(x)-g(x)
4. quotient of f and g=(f/g)(x)=f(x)/g(x)
most fuctions of notation are composition functions: which is a function inside another function.
4-3 symmetry:
*you get to draw graphs!
x-axis:
1. plug in (-y)
2. simplify=solve for y
3. if equations are equal then it has symmetry about x.
y-axis:
1. plug in (-x)
2. simplify=solve for y
3. if equations are equal then it has symmetry about y.
origin:
1. plug in (-x) and (-y)
2. simplify=solve for y
3. if equations are equal then it has symmetry of the origin.
y=x
1. switch x and y
2. solve for y
3. if equations are equal then it has symmetry for y=x
*when you draw these graphs its all about reflecting.
EVERYONE ENJOY YOUR 3 DAY WEEKEND :)
4-2
1. Sum of f and g: (f+g)(x) = f(x) + g(x)
2. Difference of f and g: (f-g)(x) = f(x) – g(x)
3. Product of f and g: (f x g)(x) = f(x) x g(x)
4. Quotient of f and g: (f/g)(x) = f(x)/g(x), provided g(x) not equaled to 0
*f(x) is a notation!
EXAMPLE 1: f(x) = 2x + 1 and g(x) = 2 – x Find the sum and difference notations.
A). (f+g)(x) = (2x+1) + (2-x)
= x + 3
B). (f-g)(x) = (2x+1) – (2-x)
= 3x -1
EXAMPLE 2: If you have f(#), f(y), or f(i^2), the notations means to plug what is in the parenthesis into the equation instead of x. Knowing this, solve (f+g)(3) using Example 1’s f(x) and g(x).
A). (f+g)(3) = (2x+1) + (2-x)
= x + 3
B). Plug in 3 into the above answer.
= 3 + 3
C). Your answer is 6.