Given that

\

$\"\"$

\

Let us take

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Substitute in the given trigonometric function

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

L . H.S = R.H.S

\