Question

If A+B=45 then prove that (cotA-1)(cotB-1)=2and find the value of COT22*1/2°

Answer 1

This is solution of part one. The solution of part two is given below.
Cot45=1
Hence cot 2(22•5)=1 from here by applying the formula of cot 2A you can derive the value of cot 22•5=(1+√2) or (1-√2).