Question

Evaluate :cos^6x-sin^6x​

Answer 1

Step-by-step explanation:

( (cos x)^3 - (sin x)^3 )( (cos x)^3 + (sin x)^3 )

=> [ (cos x - sin x){(cos x)^2 + (sin x)^2 +cos x.sin x} ] [ (cos x + sin x){(cos x)^2 + (sin x)^2 - cos x.sin x} ]

=> [ (cos x - sin x){1 +cos x.sin x} ] [ (cos x + sin x){1 - cos x.sin x} ]

=> (cos x + sin x)(cos x - sin x)(1 + cos x.sin x)(1 - cos x.sin x)