Question

Cos 2x cos 2y + sin^2 (x-y) - sin ^2 (x+y) = cos (2x+2y)

Answer 1

Answer:

To prove,

Cos 2x Cos 2y + sin^2(x-y) - sin^2(x+y) {LHS}

cos (2x+2y){RHS}

We can eliminate +sin^2(x-y) and - sin^2(x+y)

Therefore,

LHS= cos 2x cos 2y

= cos (2x+2y)

RHS= cos(2x+2y)

Hence proved, cos(2x+2y)=cos(2x+2y)..

Kudos!