\(\rm \int\frac{tan^{-1}x}{x^3}dx=\)
1
\(\rm \frac{-(x^2+1)}{2x}tan^{-1}x-\frac{1}{2x}+C\)
2
\(\rm \frac{-(x^2+1)}{2x+1}tan^{-1}x-\frac{1}{2x^2}+C\)
3
\(\rm \frac{-1}{2x}-\left(\frac{1}{2}+\frac{1}{2x^2}\right) tan^{-1}x+C\)
4
\(\rm \frac{1}{2x}+\frac{1}{2x^2}tan^{-1}x+C\)