Chapter 8.2, Problem 78E

To determine

To find:Thepartial sum ${\displaystyle \sum _{n=1}^{50}\left(40-2n\right)}$ by using graphing utility.

Answer to Problem 78E

  ${\displaystyle \sum _{n=1}^{50}\left(40-2n\right)}=-550$

Explanation of Solution

Given information:

A sequence is given as ${\displaystyle \sum _{n=1}^{50}\left(40-2n\right)}$ .

Calculation:

Consider the given partial sum.

  ${\displaystyle \sum _{n=1}^{50}\left(40-2n\right)}$

Now, use graphing utility command to calculate the sum as shown:

  $>sum\left(\left(40-2n\right),n=1,2,3,\mathrm{...},50\right)$

The calculator will display the result as shown:

  $>sum\left(\left(40-2n\right),n=1,2,3,\mathrm{...},50\right)=-550$

Thus, ${\displaystyle \sum _{n=1}^{50}\left(40-2n\right)}=-550$ .