i. We know, 2 sin A cos B = sin (A + B) + sin (A – B)

{sin (-x) = - sin x}

{sin (180° - x) = sin x}

Hence Proved

ii. We know, 2 sin A cos B = sin (A + B) + sin (A – B)

Take L.H.S

{sin (-x) = - sin x}

= R.H.S.

Hence Proved