Answer
$\sum\limits_{k=1}^{5}\frac{1}{k^2}$
Work Step by Step
We have to rewrite the sum using sigma notation:
$\frac{1}{1^2}+\frac{1}{2^2}+\frac{1}{4^2}+\frac{1}{4^2}+\frac{1}{5^2}$
Each term has the form of $\frac{1}{k^2}$, where $k=1,2,3,4,5.$
There are $5$ terms in the sum, hence the index of the sum would go from $1$ to $5$.
So in sigma notation:
$\frac{1}{1^2}+\frac{1}{2^2}+\frac{1}{4^2}+\frac{1}{4^2}+\frac{1}{5^2}=\sum\limits_{k=1}^{5}\frac{1}{k^2}$
