Practicing Success
$\int \frac{1}{x(1+\sqrt[3]{x})^2} d x$ is equal to |
$3\left\{\log \left(\frac{x^{1 / 3}}{1+x^{1 / 3}}\right)+\frac{1}{1+\sqrt[3]{x}}\right\}+C$ $3\left\{\log \left(\frac{1+x^{1 / 3}}{x^{1 / 3}}\right)+\frac{1}{1+x^{1 / 3}}\right\}+C$ $3\left\{\log \left(\frac{1+x^{1 / 3}}{x^{1 / 3}}\right)-\frac{1}{1+x^{1 / 3}}\right\}+C$ none of these |
$3\left\{\log \left(\frac{x^{1 / 3}}{1+x^{1 / 3}}\right)+\frac{1}{1+\sqrt[3]{x}}\right\}+C$ |
Let $I=\int \frac{1}{x(1+\sqrt[3]{x})^2} d x=\int \frac{1}{t^3(1+t)^2} 3 t^2 d t$ $\Rightarrow I=3 \int \frac{1}{t(t+1)^2} d t=3 \int\left\{\frac{1}{t}-\frac{1}{t+1}-\frac{1}{(t+1)^2}\right\} d t$ $\Rightarrow I=3\left\{\log _e t-\log (t+1)+\frac{1}{t+1}\right\}+C$ $\Rightarrow I=3\left\{\log _e\left(\frac{t}{t+1}\right)+\frac{1}{t+1}\right\}+C$ $\Rightarrow I=3\left\{\log _e\left(\frac{x^{1 / 3}}{1+x^{1 / 3}}\right)+\frac{1}{x^{1 / 3}+1}\right\}+C$ |