(cot^2x-1)/(1 cot^2x)=1-2sin^2

OK I found it by turning the denominator into sec2 then moving it to the top using recipricol identity followed by distribution then used a quotient identity and came to the answer

Good work. In general for these types of problems I find it easiest to convert the tangenet, cotangent, secant, and cosecant functions into their sine and cosine equivalents. I do it this way because I can remember the basic sine and cosine identies. So for this problem I would have done this:



Multiply through by sin^2x:



Then apply identities: