Step 1:

The trigonometric equation

Apply the formula

and

and

and

General solution of then .

Step 2:

Case 1:

Solve the equation 

and

For

For

For

Step 3:

Case 2:

Solve the equation 

Sine is negative in third and fourth quadrants.

The solutions are

The solution in the interval is .

Step 4:

Graph

Solution:

The solution in the interval is .