Prove that \(cot^2 \ P - cot^2 \ Q = \frac{cos^2 \ P - cos^2 \ Q}{sin^2 \ P \ sin^2 \ Q}\).
 
Proof:
Answer variants:
\(1 - sec^2 P\)
\(cos^2 P - cos^2 Q\)
\(1 - cos^2 P\)
\(1 - cosec^2 P\)
\(1 - cos^2 Q\)
LHS=cot2Pcot2Q=cos2Psin2Pcos2Qsin2Q=cos2Psin2Qcos2Qsin2Psin2Psin2Q=cos2Picos2Qisin2Psin2Q=cos2Pcos2Pcos2Qcos2Q+cos2Qcos2Psin2Psin2Q=isin2Psin2Q