Question

1-tan^2a=2tana/1-tan^2a​

Answer 1

It may be like this,

tan (2A) = 2tanA/(1-tan²A)

We know that,

$\boxed {tan(A+B)=\frac{tanA+tanB}{1-tanA\times tanB}}$

Now ,

LHS = tan(2A)

=tan(A+A)

=$\frac{tanA+tanA}{1-tanA\times tanA}$

= $\frac{2tanA}{1-tan^{2}A}$

= $RHS$

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