$\"\"$

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

$\"\"$ (Since $\"\"$ function is negative in third quadrant)

$\"\"$

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

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

If $\"image\"$ , then $\"\"$ ,

If $\"image\"$ , then

$\"\"$

Thus, the solutions are $\"\"$ and $\"\"$ in the interval $\"\"$ . $\"\"$

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