$\"\"$

The trigonometric equation is $\"\"$ .

Let the functions are $\"\"$ and $\"\"$ .

Draw a coordinate plane.

Graph the two functions $\"\"$ and $\"\"$ on the interval $\"\"$ in same window.

Graph :

$\"\"$

Observe the above graph :

The two functions intersects at $\"\"$ on the interval $\"\"$ .

$\"\"$

The solution of $\"\"$ is $\"\"$ on the interval $\"\"$ .