Verify the identity. (Simplify at each step.) 9 tan x + 9 cot y / tan x cot y = 9 tan y + 9 cot x Verify the identity. (Simplify at each step.) sin^2 beta + sin^2 (pi/2 - beta) = 1 Verify the identity. (Simplify at each step.) tan^6 x = tan^4 x sec^2 x - tan^4 x