Differentiate the following functions with respect to $x$ :
$\tan ^{-1}\left\{\frac{x^{1 / 3}+a^{1 / 3}}{1-(a x)^{1 / 3}}\right\}$
$y=\tan ^{-1}\left(\frac{x^{\frac{1}{3}}+a^{\frac{1}{3}}}{1-(a x)^{\frac{1}{3}}}\right)$
Arranging the terms in equation
$y=\tan ^{-1}\left(\frac{x^{\frac{1}{3}}+a^{\frac{1}{3}}}{1-x^{\frac{1}{3}} \times a^{\frac{1}{3}}}\right)$
Using, $\tan ^{-1} x+\tan ^{-1} y=\tan ^{-1}\left(\frac{x+y}{1-x y}\right)$
$y=\tan ^{-1}\left(x^{\frac{1}{3}}\right)+\tan ^{-1}\left(a^{\frac{1}{3}}\right)$
Differentiating w.r.t $\mathrm{x}$ we get
$\frac{d y}{d x}=\frac{d}{d x}\left(\tan ^{-1}\left(x^{\frac{1}{3}}\right)+\tan ^{-1}\left(a^{\frac{1}{3}}\right)\right)$
$\frac{d y}{d x}=\frac{3}{1+\left(x^{\frac{1}{3}}\right)^{2}} \times \frac{d}{d x}\left(x^{\frac{1}{3}}\right)$
$\frac{\mathrm{dy}}{\mathrm{dx}}=\frac{3}{1+\left(\mathrm{x}^{\frac{1}{3}}\right)^{2}} \times \frac{1}{3}\left(\mathrm{x}^{-\frac{2}{3}}\right)$
$\frac{d y}{d x}=\frac{1}{3 x^{\frac{2}{3}}\left(1+\left(x^{\frac{1}{3}}\right)^{2}\right)}$