You are expected to know these double-angle identities:
We have: .
Very tough... I am thinking now of working with the right side and doing :(1+cosx)/sinx = cot(x/2)
cot(x/2) * cot(2x)/cot(2x)
= cot^2x/cot2x // Is this true?
because I have no idea what to do when I am given some thing like (x/2)
Any hints are really appreciated
Do you know the "sum" formulas: sin(A+ B)= sin(A)cos(B)+ cos(A)sin(B) and cos(A+ B)= cos(A)cos(B)- sin(A)sin(B)?
Setting A= B= X gives the "double angle" formulas: sin(2X)= 2sin(X)cos(X) and cos(2X)= cos^2(X)- sin^2(X)
Letting Y= 2X in that last lets us derive the "half angle" formulas:
And, of course, and