Solution :
The formula of cot (A – B) is \(cot A cot B + 1\over cot B – cot A\).
Proof : We have,
cot (A – B) = \(cos (A – B)\over sin(A – B)\)
Using sin (A – B) and cos (A – B) formula,
cot (A – B) = \(cos A cos B + sin A sin B\over sin A cos B – cos A sin B\)
Dividing the numerator and denominator by sin A sin B,
cot (A – B) = \(cot A cot B + 1\over cot B – cot A\)
Similar Formulas
What is the Formula of Tan (A + B) ?
