Charlie's Blog #3

This week we basically reviewed for the Chapter 7 test. Which was degree's to rads, rads to degrees, coterminal angles, minutes & seconds, the central angle stuff, sin & cos, reference angles, tan sec cot & csc, inverses, and the trig chart. But at the end of the week we took Chapter 8 notes.


To solve for theta you get the trig. function by itself &then take an inverse.

An inverse has 2 answers with some exceptions. Find where the angle is based on the trig. function &if the number is positive or negative.

For 8-1 theres easy steps to follow..
1.) Take the inverse of the positive number to find the quadrant 1 angle
2.) to get to:
-quadrant 2= make negative degree & add 180 degrees
-quadrant 3= add 180 degrees
-quadrant 4= make negative and add 360


**For example:

Cos x=.9
x=cos^-1(.9)
x=.451 degrees
inverse of .451; -.451 + 360
x=1.103 degrees; 359.549 degrees

In this problem cos is positive over positive which deals with the x axis. So this means we have to find the first and the fourth quadrant. To get the first we took the inverse of .451 and to get the fourth quadrant we made .451 negative and added 360, this gives us both answers.