Question:
Differentiate the following functions with respect to $x$ :
$\tan ^{-1}\left(\frac{2 a^{x}}{1-a^{2 x}}\right), a<1,-\infty
Solution:
$\mathrm{y}=\tan ^{-1}\left\{\frac{2 \mathrm{a}^{\mathrm{x}}}{1-\mathrm{a}^{2 \mathrm{x}}}\right\}$
Let $\mathrm{a}^{\mathrm{x}}=\tan \theta$
$\mathrm{y}=\tan ^{-1}\left\{\frac{2 \tan \theta}{1-\tan ^{2} \theta}\right\}$
Using $\tan 2 \theta=\frac{2 \tan \theta}{1-\tan ^{2} \theta}$
$\mathrm{y}=\tan ^{-1}(\tan 2 \theta)$
Considering the limits,