<a href="http://www.codecogs.com/eqnedit.php?latex=u=x^3-1 \\ \frac{du}{dx}=3x^2\\ du=3x^2dx\\ \therefore \int 3x^2\sqrt(x^3-1)=\int \sqrt(u)du\\ =\frac{2(u)^\frac{3}{2}}{3}\\ =\frac{2}{3}(x^3-1)^\frac{3}{2}@plus;C" target="_blank"><img src="http://latex.codecogs.com/gif.latex?u=x^3-1 \\ \frac{du}{dx}=3x^2\\ du=3x^2dx\\ \therefore \int 3x^2\sqrt(x^3-1)=\int \sqrt(u)du\\ =\frac{2(u)^\frac{3}{2}}{3}\\ =\frac{2}{3}(x^3-1)^\frac{3}{2}+C" title="u=x^3-1 \\ \frac{du}{dx}=3x^2\\ du=3x^2dx\\ \therefore \int 3x^2\sqrt(x^3-1)=\int \sqrt(u)du\\ =\frac{2(u)^\frac{3}{2}}{3}\\ =\frac{2}{3}(x^3-1)^\frac{3}{2}+C" /></a>