Answer
$2 (\sin 5 \theta +\sin \theta)$
Work Step by Step
By using the Sum and Difference formulas: $\sin (a+b)=\sin a \cos b +\cos a \sin b$ and $\sin (a-b)=\sin a \cos b -\cos a \sin b$
Now, we will write the expression:
Therefore,$\dfrac{4}{2}[\sin 3 \theta +2 \theta +\sin 3 \theta-2 \theta]$
or, $=2 (\sin 5 \theta +\sin \theta)$
