tan2θ1+tan2θ + cot2θ1+cot2θ =
2
0
-1
1
tan2θsec2θ + cot2θcosec2θ
= sin2θcos2θ1cos2θ + cos2θsin2θ1sin2θ = sin2θ + cos2θ = 1
11+tan2θ+11+cot2θ=