Question

Find (x,y) on the unit circle, given that the x-coordinate of P is -1/2 and P is in Quadrant III?

Answer 1

See below

Explanation:

From the diagram:

Distance `bb(a) = -1/2`

`x=bb(a)=cosalpha=-1/2=>alpha=(-2pi)/3`

`y=bb(b)=sinalpha=sin(-(2pi)/3)=-sqrt3/2`

`( x,y)->( -1/2,-sqrt(3)/2)`