# How do you use sigma notation to represent the series 1/2+1/4+1/8+…?

$\frac{1}{2} + \frac{1}{4} + \frac{1}{8} + \cdots = \frac{1}{2} ^ 1 + \frac{1}{2} ^ 2 + \frac{1}{2} ^ 3 + \cdots = {\sum}_{n = 1}^{\infty} \frac{1}{2} ^ n$