Establishing an Identity
Establishing the identity: {\frac{\cos\left(\alpha-\beta\right)}{\sin\alpha\sin\beta}}=\cot\alpha\cot\beta+1
={\frac{\cos\alpha\cos\beta}{\sin\alpha\sin\beta}}+{\frac{\sin\alpha\sin\beta}{\sin\alpha\sin\beta}}
={\frac{\cos\alpha}{\sin\alpha}}\cdot{\frac{\cos\beta}{\sin\beta}}+1
=\cot\alpha\cot\beta+1