For each given angle first find the reference angle and then

For each given angle, first find the reference angle and then evaluate sine, cosine, and tangent of the angle without using your calculator. 10 pi/3 -9 pi/4

Solution

a. 10pi/3

The given angle is in third quadrant. Therefore reference angle is 4pi/3 -pi=pi/3

sin pi/3= sqrt3/2

cos pi/3=1/2

tanpi/3=sqrt3

b. -9pi/4

Reference angle is pi/4

sin pi/4= sqrt2/2

cos pi/4=sqrt2/2

tan pi/4=1