Question

From the formaula sin (a+b) =sin a cos b +cos a sin b, deduce that sin 2A =2 sin A cos A

Answer 1

Answer:

$\sin( 2a) = \sin(a + a ) \\ \sin(a) \cos(a) + \cos(a) \sin(a ) \\ 2 \sin(a) \cos(a)$