The trigonometric equation is .

Subtract from each side.

Divide each side by .

Apply reciprocal identity : .

and .

First solve .

or

or

The general solution of is , where is an integer.

The solutions are or , where is an integer.

Now solve .

or

or

The general solution of is , where is an integer.

The solutions are or , where is an integer.

The solutions are ,  , , and where is an integer.