TITLE: Indefinite integral: $\int \frac{\mathrm dx}{\sqrt x(1+\sqrt[3]x)}$
QUESTION [6 upvotes]: I need :

$$ \int \frac{\mathrm dx}{\sqrt{x}(1+\sqrt[3]{x})}$$

Can you give me a hint, which way would suit best? I tried substitution, but don't have an idea what to substitute.. :/

REPLY [2 votes]: $$
\int\frac{dx}{\sqrt x\left(1+\sqrt[3]{x}\right)}=\int\frac{dx}{\sqrt[6]x^{3}\left(1+\sqrt[6]{x^2}\right)}=|\sqrt[6]{x}=t\Rightarrow x=t^6\Rightarrow dx=6t^5dt|
$$
$$
=\int\frac{6t^5dt}{t^3\left(1+t^2\right)}=6\int\frac{t^2dt}{1+t^2}=6\int\frac{t^2+1-1}{1+t^2}dt=6\int\left(1-\frac{1}{1+t^2}\right)dt
$$
$$
=6\int dt-6\int \frac{1}{1+t^2}dt=6t-6\arctan t=6(\sqrt[6]{x}-\arctan \sqrt[6]{x})+C
$$