kaitlyn's holiday blog 4

chapter 7-4!!!!
this chapter deals with finding reference angles for different functions.


steps: 1)figure out which quadrant the angle is in
2)determine whether or not the function is positive or negative
3)subtract 180 from the angle until it is between 0 and 90
4)once you do that, either use your trig chart or a calculator to find the answer.


Example: find the reference angle for sin420
-this is in quadrant 1
-sin is positive in quadrant 1
-if you keep subtracting 180 from 420, you will get 60
-sin60=(squarerootof3/2) <---answerrrrr


Example: find the reference angle for cos210
-thsi is in quadrant 3
-cos is negative in quadrant 3
-if you keep subtracting 180 from 210, you will get 30
-cos30=(-squarerootof3/2) <---answerrrrr