Question

Sketch a unit circle and label the terminal points corresponding to t= pi/4, 3pi/4, 5pi/4, 7pi/4.

Include the coordinates of each point.

I have 3 other problems like this and i have no clue how to do them. can someone help please?

Answer 1

x is at cos (angle)
y is at sin (angle)

so for example if angle is pi/4
x = cos(pi/4) = sqrt(2)/2
y = sin(pi/4) = sqrt(2)/2
so ( sqrt(2)/2 , sqrt(2)/2 )

if 3 pi/4 (45 deg in Quadrant 2)
x = -sqrt(2/2)
y = +sqrt(2)/2 etc