Identify the point (x,y) on the unit circle that corresponds to t = - π

Question

( ? , ? )

Answer 1

pi=180 so -180 would be on the third quadrant and since 180 is half the circle then only the x coordinate will have a value within this unit circle and since the radius of the unit circle is 1 and the first quadrant has a positive x value of 1 and -180 corresponds to 0 and because the (x,y) coordinates can be found by cos(a), sin(a)) then (cos(0),sin(0)=sqrt(4)/2 or 2/2 which is equal to 1 and sin(0)=sqrt(0)/2 which is just 0 so the resulting (x,y) coordinate for -pi is (1,0).