im trying to integrate the function $\displaystyle x(1-x)$ which is $\displaystyle x-x^2$. if I make u=x^2 or u=x-x^2 for u-substitution it never turns out right though.. please someone help
u-substitution?! this is power rule!
remember, $\displaystyle \int x^n ~dx = \frac {x^{n + 1}}{n + 1} + C$ ........(for any constant $\displaystyle n \ne -1 $ of course )
here you have $\displaystyle \int x^1~dx - \int x^2~dx$, just integrate each separately using the power rule