Can you help me prove this equation?

Question

(sin+1)(sin-1)=cotsin-2cos

Answer 1

NO, I CANNOT because it's a mess.

Whenever you write sin (i.e. sine), there must be an ARGUMENT, i.e. sine of some Real number, e.g. sin x or sin θ.

Also, what on Earth does "cotsin" mean?

 

This needs serious revision, asap.