Question

Evaluating a Sum Using a graphing calculator to evaluate the sum.

$\sum _{n=1}^{100}\frac{{\left(-1\right)}^n}{n}$

Short answer

The sum is −0.68817217931.

Step-by-step solution

Step 1.  Given

The given sequence is$\sum _{n=1}^{100}\frac{{\left(-1\right)}^n}{n}.$

Step 2.  To determine

We have to find thesum of the given sequence using a graphing calculator.

Step 3.  Calculation

We’ll use Desmos graphing calculator to evaluate the sum.

Using the virtual key board, we enter the given expression $\sum _{n=1}^{100}\frac{{\left(-1\right)}^n}{n}.$

We get:

Hence, the sum is −0.68817217931.