Question

Question #adbff

Answer 1

As below

Explanation:

`cot3x=cot(2x+x)`

Using formula

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

`=>cot3x=(cot2xcotx-1)/(cot2x+cotx)`

`=>cot2xcotx-1=cot3x(cot2x+cotx)`

`=>cot2cotx-1=cot3xcot2x+cot3xcotx`

`=>cotxcot2x-cot2xcot3x-cot3xcotx=1`

Proved