Precalculus Examples

$\sum_{n = 1}^{8} 5 {(r)}^{n - 1}$

Step 1

Factor $5$ out of the summation.

$(5) \sum_{n = 1}^{8} r^{n - 1}$

Step 2

Expand the series for each value of $n$ .

$5 r^{1 - 1} + 5 r^{2 - 1} + 5 r^{3 - 1} + \dots + 5 r^{8 - 1}$

Step 3

Simplify the expanded form.

$0$