Question

Q.7
Prove that
(sin 7x+sin 5x)+(sin 9x+sin 3x)
- = tan 6x
(cos 7x+cos 5x )+(cos 9x+cos3x)​

Answer 1

Answer:

take the l.h.s

sin 7x+ sin 5x + sin 9x + sin 3x

sin 24x.

take r.h.s

tan 6x ( cos 7x + cos 5x + cos 9x + cos 3x

sin 6x/cos 6x ( cos 24x)

sin 24x.

lhs=rhs