$\"\"$

The trigonometric equation is $\"\"$ .

Consider $\"\"$ .

Rewrite the equation as $\"\"$ .

Apply double angle formula : $\"\"$ .

$\"\"$ .

$\"\"$

Graph :

Draw a coordinate plane.

Graph the function $\"\"$ in the interval $\"\"$ .

$\"graph$

$\"\"$

Graph of the function $\"\"$ is :

$\"graph$