Question

Tan x-1/tan x+1=1-cot x/1+cotx

Answer 1

`(\tan x-1)/(\tan x+1)=((\sin x)/(\cos x)-1)/((\sin x)/(\cos x)+1)=(\sin x-\cos x)/(\sin x+\cos x)=(1-(\cos x)/(\sin x))/(1+(\cos x)/(\sin x))=(1-\cot x)/(1+\cot x)`