- #1

Mdhiggenz

- 327

- 1

## Homework Statement

Find a closed form for the nth partial sum, and determine whether the series converges by calculating the limit of the nth partial sum.

1. 2+2/5 + 2/25+...2/5

^{k-1}

## Homework Equations

## The Attempt at a Solution

What I did was I found out it was a geometric sequence.

with R = .2

s

_{n}=2+2/5+2/25+2/5

^{n-1}

.2s

_{n}= 2/5+2/25+2/125+2/5

^{n}

I subtract the equations giving me

.8s

^{n}=2+2/5

_{n}

I divide .8 to both sides giving me

s

_{n}= 5/2+1/2

^{n}

I know I am messing up with the multiplication / subtraction of the Nth term much help is appreciated (: