Question

prove : 1- tan^2a/ cot^2a-1= tan^2a

Answer 1

Given,
1 - tan ² A / cot ² A - 1
= sec ² A / cosec ² A ( using fundamental relationship)
sin ² A / cos ² A
= tan ² A proved

Answer 2

Hope you get it. If you have any doubt you could ask