It's not an equation, it's an identity.
The left side member:
Then the identity holds.
Thanks for the help but equation I posted earlier was not the equation I was stuck with, actually following is the equation I want to solve-
1+tan^2 A/1+cot^2 A= (1-tan A/1-cot A)^2
sorry for the trouble, any further help will be appreciated.
Thanks