1. The problem statement, all variables and given/known data (1-cos^2x)(1+tan^2x) = tan^2x 2. Relevant equations N/A 3. The attempt at a solution (1-cos^2x)(1+tan^2x) = tan^2x L.S. = (sin^2x)(1+sin^2x/cos^2x) = sin^2x+(sin^4x/cos^2x) Now, I get a common denominator, but it's not doing anything for me. Did I do the right thing in converting the tan?