Question

Cot 30° cot 60°-1÷cot 30°+cot 60°=cot 90°

Answer 1

Step-by-step explanation:

There is a formula

cot(A+B) = (cotA.cotB - 1) / (cotA + cotB)

So, compare that question with this formula we get,

(Cot 30° cot 60°-1) / (cot 30°+cot 60°)

= cot(30°+60°)

which is equal to cot90°

Hence proved