Question

Find ∫(cos²2x − sin²2x)dx

Answer 1

Answer:

it is a question of math not Indian language....

Answer 2

1.∫(cos²2x − sin²2x)dx is sin4x/4+c

2.To solve this we know a formula

consider α as any angle

ie cos²α-sin²α=cos 2α (by trigonometry )

so

3.cos²2x-sin²2x=cos2×2x(considering α=2x in above formula)

cos²2x-sin²2x=cos4x

4.we know that ∫cosx=sinx+c

so ∫cos 4x=sin4x/4+c