The trigonometric equation is $\"\"$ .

Double-angle formula : $\"\"$ .

$\"\"$

Separate the solutions.

$\"\"$ and $\"\"$ .

Simplify and rewrite the equations.

$\"\"$ and $\"\"$ .

General solution for $\"\"$ : $\"\"$

General solution $\"\"$ :

If $\"\"$ , then $\"\"$ , where $\"\"$ is an integer.

$\"\"$

In the interval $\"\"$ the general solution is

$\"\"$

The solution of the trigonometric equation is $\"\"$ .

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