The equation is $\"\"$ on interval $\"\"$ .

Consider $\"\"$ .

$\"\"$

$\"\"$ .

To solve $\"\"$ on a calculator, first set the mode to radians.

If $\"\"$ .

$\"\"$ .

General solution of $\"\"$ is $\"\"$ , where $\"\"$ is an integer.

$\"\"$ .

Take $\"\"$

$\"\"$

$\"\"$ .

Take $\"\"$ .

$\"\"$

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