Proofs of Triple Angle Identities

Lesson#3
Proofs of Triple Angle Identities
Triple Angle Identities
1) sin⁡3α=3 sin⁡α−4 sin^3 α
2) cos 3α=4 cos^3 α−3 cosα
3) tan⁡3α=(3 tan⁡α−tan^3 α)/(1−3tan^2 α)
Math.Ex.10.3, Part3-10.3
Prove the following identity:
sin⁡3α=3 sin⁡α−4 sin^3 α
cos 3α=4 cos^3 α−3 cosα
tan⁡3α=(3 tan⁡α−tan^3 α)/(1−3tan^2 α)
Trigonometric Identities
Chapter No 10
Exercise No 10.3
Mathematics
part 1