Chapter 5.4, Problem 1QCE

(a) Write the sum in two ways:

$\frac{1}{2}+\frac{1}{4}+\frac{1}{6}+\frac{1}{8}={\displaystyle \underset{k=1}{\overset{4}{\sum }}\text{\_\_\_\_\_\_\_}}={\displaystyle \underset{j=0}{\overset{3}{\sum }}\text{\_\_\_\_\_\_\_}}$

(b) Express the sum $10+{10}^2+{10}^3+{10}^4+{10}^5$ using sigma notation.