Download between its terminal side and the xaxis. The trigonometric functions

Section 3.1­­Reference Angles
The reference angle of any angle in standard position is the acute angle between its terminal side and the x­axis. The trigonometric functions of the angle and its reference angle differ at most in the sign dictated by the quadrant.
o
45 is the reference angle
o
reference angle is 30
150o
315o
Draw the angles in standard position and find the reference angles:
240o
60o
210o
330o
Find the exact value of each of the following:
cos 135o
cot 510o
Why bother with reference angles?
If you know a trig function of an angle, but you know the angle is in a certain quadrant, you can adjust the angle to that quadrant.
If sin θ = 1/2 and you know that θ is in quadrant 2, what will θ be?
If tan θ = ­1 and θ is in quadrant 2, what is θ?
cos θ = ­0.7660, θ is in Q2