$\"\"$

The trigonometric equation is $\"\"$ and the interval is $\"\"$ .

$\"\"$ .

$\"\"$

The general solution of $\"\"$ is $\"\"$ , where $\"\"$ is an integer.

$\"\"$ $\"\"$

For $\"\"$ , $\"\"$ .

For $\"\"$ ,

$\"\"$ .

The solutions in the interval $\"\"$ are $\"\"$ .

$\"\"$

The solution set for $\"\"$ is $\"\"$ .