Question

prove that the following questions ​

Answer 1

Answer:

sinx(sin3x + sinx) = sinx(2 sin2x cosx)     ...(1)

cosx(cos 3x - cos x) = cosx(-2sin2x sinx)        .....(2)

(1) +(2)  =2sinx sin2x cosx - 2sinx sin2x cosx = 0