Please help me with this

Question

Find the exact coordinates (x,y) of the point at angle -90° on a circle of radius 6 centered at the origin.

The point (x,y) is

Answer 1

You can either draw a graph and see the point is actually on the negative y-axis and the point is given by (0,-6).

Or

For any point on the circle centered at the origin, the coordinate can be found by (RcosΘ, RsinΘ) where Θ is the angle from the positive x-axis counterclockwise. Here we have the radius R=6, Θ=-90°,

(RcosΘ, RsinΘ)=(6cos(-90°), 6sin(-90°))=(0, -6).

Answer 2

(0,6)

90 degrees is vertically above the origin, 6 units up.