Question

Let $\tan A=3$, then find the value of $\tan 2A$.

Answer 1

Given $\tan A=3$.

Now $\tan 2A$

$=\frac{2\tan A}{1-{\tan }^{2}A}$ [ Using formula for $\tan 2A$]

$=\frac{2\times 3}{1-3^2}$

$=-\frac{3}{4}$.