## anonymous 3 years ago Simplify using the double-angle formula: x3 - 2x3 sin2 (x + 1). A. x3 cos (x + 1) B. x3 cos (2x + 1) C. x3 cos 2(x + 1) D. x3 cos2 (x + 1)

1. anonymous

can someone help me

2. sasogeek

I can't help you with this one, but I'll try to find someone else who can :) alright?

3. .Sam.

$x^3 - 2x^3 \sin^2 (x + 1)$ First factor out $$x^3$$ $x^3(1-2\sin^2(x+1))$ let u=x+1 $x^3(1-2\sin^2(u))$ Using identity $\cos(2u)=1-2\sin^2(u),$we have $x^3\cos(2u)$ Then $x^3\cos(2(x+1))$