Question

sin 3x + sin 2x - sin x = 4 sin x cos x / 2 cos 3 X /2 .prove that​

Answer 1

sin 3x+sin 2x-sin x=4 sin x cos x/2 cos 3x/ 2 .prove that

=(sin 3x+sin 2x)-sin x

=sin+ sin D=2 sin C+D/2 cos C-D/2

=2 sin sx/2 cos x/2-2 sin x/2

=2 cos x/2 [sin s/2 -sin x/2] cos x/2

=sin C- sin D=2 cos +D/2 sin C-D/2

=2 cos x/2 ×2 cos [(Sx/2+x/2)\2] sin (sx/2 x/2)

2 soc x/2 ×2cos 3x/2 sin

4 sin x cos x

RHS=LHS