The trigonometric equation is .

Apply pythagorean identity : .

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Consider .

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. 

General solution of is , where is an integer.

General solution is , where is an integer.

Find the angle in the interval .

General solution is , where is an integer.

If , .

If , .

Thus, the solutions are and in the interval . 

Consider .

.

General solution of is , where is an integer.

General solution is , where is an integer.

Find the angle in the interval .

General solution is , where is an integer.

If , .

If , .

Thus, the solutions is in the interval .

Thus, the solutions are , , and in the interval . 

The solutions are , , and in the interval .