SOLUTION: Prove: 1-cot^2x/1+cot^2x=2cos^2-1 I tried this: LHS =1-(cos^2x/sin^2x)/csc^2x =(sin^2x-cos^2x/sin^2x)/(1/sin^x) =sin^2x-cos^2x/sin^2x(sin^2x/1) sin^^2x-cos^2x RH

Algebra ->  Trigonometry-basics -> SOLUTION: Prove: 1-cot^2x/1+cot^2x=2cos^2-1 I tried this: LHS =1-(cos^2x/sin^2x)/csc^2x =(sin^2x-cos^2x/sin^2x)/(1/sin^x) =sin^2x-cos^2x/sin^2x(sin^2x/1) sin^^2x-cos^2x RH      Log On


   

Question 889242: Prove:
1-cot^2x/1+cot^2x=2cos^2-1


I tried this:
LHS
=1-(cos^2x/sin^2x)/csc^2x
=(sin^2x-cos^2x/sin^2x)/(1/sin^x)
=sin^2x-cos^2x/sin^2x(sin^2x/1)
sin^^2x-cos^2x
RHS
2cos^2-1=cos(2x)

So, after this, I don't know what to do. Thank you!
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
sin^2(x) - cos^2(x) = cos(2x)