Question

(1+tan)(tan2x)=2tanx/1-tanx I need to prove that the equation is an identity.

Answer 1

tan (2x) = tan (x+x) = \(\dfrac{2tanx}{1-tan^2x}\) replace to tan 2x from the left hand side
(1+tan x ) * \(\dfrac{2tanx}{1-tan^2x}\)= right handside