$\"\"$

\

The equation is $\"\"$ .

\

(Apply double angle formula: $\"\"$ )

\

$\"\"$

\

(Subtract $\"\"$ from each side)

\

$\"\"$

\

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

\

$\"\"$ (Take out common factor)

\

$\"\"$ (Apply zero product property)

\

$\"\"$

\

$\"\"$

\

The values are $\"\"$ $\"\"$

\

The solutions are $\"\"$ .