BIN0MI1L

The integration method works here

(1+x)^n=\sum{^nC_rx^r}

\int (1+x)^n=\sum\int{^nC_rx^r}

(1+x)^{n+1}=\sum\int{^nC_rx^{r+1}/r+1}

divide by x and integrate again.. you are done..

This is a way to find

\sum{}r \begin{pmatrix}n\\ r\end{pmatrix}

can you do that? or say

\sum{}r^2 \begin{pmatrix}n\\ r\end{pmatrix}

or

\sum{}1/r \begin{pmatrix}n\\ r\end{pmatrix}