Question

Solve (cos Θ - cos Θ)^2 + (cos Θ + cos Θ)^2.

Answer 1

@DanJS

Answer 2

let costheta = a
so replace all cos x by a \[\huge\rm (a-a)^2+(a+a)^2\]
both terms are same so you can combine them

Answer 3

solve what

Answer 4

@DanJS (cos Θ - cos Θ)^2 + (cos Θ + cos Θ)^2

Answer 5

4cos^2x

Answer 6

yes