# LOOK HERE: Analysis

## Homework Statement

Let X be a normed linear space. Prove that X is complete if and only if $$\sum^{\infty}_{n=1} x_{n}$$ converges in X for all sequences ($$x_{n}$$) that satisfy $$\sum^{\infty}_{n=1} \left\|x_{n}\right\|$$< $$\infty$$