8-1

On Friday, we started Chapter 8. Although we did not get much time in we learned 8-1 which is more about inverses.To refresh an inverse (-1) finds an angle where the function has a certain value.

Ex. Sin^-1 (#) or arcsin (#)
Cos^-1(#) or arcos(#)

In order to solve for trig in 8-1 you must first get the function by itself and then take the inverse. This takes you back to what you learned in Algebra to getting variables by themselves. With inverses there will be 2 answers, with a few exceptions. The next thing to do is find where the angle is based on trig function and if number is positive or negative.

Steps:
1. Take the inverside of the postive number to find the Q1 angle.
To get either Q2, Q3, or Q4 follow these rules--
Q2: make negative, add 180degrees
Q3: Add 180degrees
Q4: Make positive, add 360degrees

Ex- Solve for sinx=.8

Sin^-1=(.8) *Sin is postive in both quadrants 1 and 2.
In calculator once you plug in Sin^-1(.8) the answer you get is 53.130. Now you need to find the second quadrant. Your rules say to make the number negative then add 180 degrees. This gives you the answer 49.988.

x=53.130, 49.988

In the case of having to get a trig function alone for example:
5sin + 10 = 15 you would do your normal steps until getting to the form of theta=sin^-1(#)