$ x\left[n\right]= \sqrt{n}*u \left [ n \right ] $
$ E_{\infty}=\sum_{n=-\infty}^{\infty} \left | x \left[ n \right ] \right | ^2 = \lim_{N \rightarrow \infty } \sum_{n=-N}^{N} \left | x \left[ n \right ] \right | ^2 $
$ E_{\infty}=\sum_{n=-\infty}^{\infty} \left | \sqrt{n}*u \left [ n \right ] \right | ^2 $
$ E_{\infty}=\underbrace{\sum_{n=-\infty}^{-1} \left | \sqrt{n}*u \left [ n \right ] \right | ^2}_{0} + \sum_{n=0}^{\infty} \left | \sqrt{n}*u \left [ n \right ] \right | ^2 $
$ E_{\infty}=\sum_{n=0}^{\infty} n = \lim_{N \rightarrow \infty } \sum_{n=0}^{N} n $
$ E_{\infty}= \lim_{N \rightarrow \infty } \frac{N \left ( N+1 \right ) }{2} =\infty $
$ P_{\infty}=\lim_{N \rightarrow \infty } \frac{1}{2N + 1} \sum_{n=-N}^{N} \left | x \left[ n \right ] \right | ^2 $
$ P_{\infty}=\lim_{N \rightarrow \infty } \frac{1}{2N + 1} \sum_{n=-N}^{N} \left | \sqrt{n}*u \left [ n \right ] \right | ^2 $
$ P_{\infty}=\lim_{N \rightarrow \infty } \frac{1}{2N + 1} \sum_{n=0}^{N} n $
$ P_{\infty}=\lim_{N \rightarrow \infty } \frac{1}{2N + 1} \frac{N \left ( N+1 \right ) }{2}=\infty $
