`2(1-2sin^2 7theta)sin3theta` is equal to `adot\ sin 17theta-sin 11theta` b. `sin11theta-sin 17theta` c. `cos 17theta-cos 11theta` d. `cos 17theta+cos 11theta`

Explanation

We have,



`2(1-2 sin ^{2} 7 theta) sin 3 theta=2(cos 14 theta) sin 3 theta`

`[ cos 2 theta=1-2 sin ^{2} theta]`

`=2 sin 3 theta cos 14 theta `

`=sin 17 theta-sin 11 theta`

`[ 2 sin A cos B=sin (A+B)-sin (A-B)]`

...