how to proof that the following one is true
$\sin2 \theta + \cos2 \theta = \sin \theta + \cos \theta$
I tried to do like this
L.H.S.
$= 2\sin\theta\cos\theta + \cos^2 \theta - \sin^2 \theta $
$= \sin\theta\cos\theta + \cos^2 \theta + \sin\theta\cos\theta - \sin^2 \theta$
$= \cos \theta(\sin\theta + \cos \theta) + \sin \theta(\cos\theta - \sin \theta)$
Then what should I do ?
Am I on the right way ?