Thread: two trig proofs

Proof number one:

prove that

Proof number two:

prove that

Any help is appreciated!

In Q1, try replacing cos 2x with cos^2 x - sin^2 x , factorise DOTS and cancel.
Then start with RHS and replace sin 2x with 2 sinx cos x and think about what you could replace the 1 with.

In Q2,
get both sides in terms of sin x and cos x only