Question

Prove that
2 / cotx tan2x = 1 - tan^2x​

Answer 1

tan2x = 2tanx / (1- (tanx)^2).

2 / (cotx.tan2x)

= 2 * ( 1- ( tanx )^2) / (cotx * 2tanx)

》》[ cotx.tanx = 1]

= ( 1 - (tanx)^2).