Sunday, September 12, 2010

Chapter 8

I personally understand and think that chapter 8 was much easier than charpter 7 so far. In section 8-1, we are trying to solve for theta or x. When you are solving for theta, you need to get the trig function alone and take the inverse of it.
- Most inverses have two answers, so if you do not end up with two, you know you are doing something wrong. Find where the answer is on the coordinate plane and figure out whether the equation is negative or positive. You need to know these steps in order to be able to solve the problem.
- To get to the quadrant 1 angle, you just take the inverse of the positive or negative.
- If you need the quadrant 2 angle, you make the number negative and add 180 degrees.
- For quadrant 3, you simply add 180 degrees.
- And quadrant 4, make the number negative and add 360 degrees.

For example: solve for theta. 4cos theta + 7 = 6
a. subract 7 from both sides. 4cos theta = -1
b. divide 4 from both sides. cos theta = -1/4
c. now get the inverse of cos. theta = cos ^-1(1/4)
d. cos^-1= 75.522 <------ this angle goes into the first quadrant, so you now have one angle.
e. Since cos deals with x and the first angle is positive, you need to figure out where the next angle will be. In this example, it will be in quadrant 4.
f. Now you make 75.522 negative and add 360 degrees.
g. the answer you end up with is 284.478

It seams that 8-1 is not that much different than chapter 7 aside from a couple of new formulas.

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