Question

sin x + sin 3 x/ cos x + cos 3 x = tan 2x​

Answer 1

Answer:

tan2x

=R.H.S

Step-by-step explanation:

LHS=sinx+sin3x/cosx+cos3x

=2sin[x+3x/2]cos[x-3x/2] / 2cos[x+3x/2]cos[x-3x/2]

=sin2x/cos2x

=tan2x

=RHS

hence proved