Hello, DesiKid89!

Suppose and

Find each of the following . . .

Sine is positive in Quadrants 1 and 2.

Tangent is negative in Quadrants 2 and 4.

. . Hence, is in Quadrant 2.

We have the identity: .

We are given: .

Hence: .

Since is in Quadrant 2: .

Back to the problem:

Are you getting the idea?

Can you do the rest?