
Let P(x,y) be a point on the unit circle with centre at origin such that angle AOP = θ. If angle AOQ = θ, then the coordinates of the point Q will be (x,y). Hence cos(θ) = x = cosθ sin(θ) = y = sinθ
In the second quadrant, as θ increases from to π/2 to π,to π sinθ decreases from 1 to 0. In the third quadrant, as θ increases from π to 3π/2, sinθ decreases from 0 to 1. In the fourth quadrant, sinθ increases from 1 to 0, as θ increases from 3π/2 to 2π.
Directions: Solve the following. 