Series: Definitions and Properties problem

[Slimsta]

Homework Statement

[PLAIN]http://img528.imageshack.us/img528/7061/37557155.jpg

Homework Equations

The Attempt at a Solution

i don't understand, what can possibly wrong with this :S
I checked it so many times over and over but everything seems to be right..
i don't even have this feeling about any of those that one is might be something else.. I am 99.9% sure about everything

 

[rs1n]

This: $\{ a_n \}_{n=1}^m$ is not a series (i.e. not a sum); this is a list of elements (i.e. a sequence).

 

[Slimsta]

oh i see.. little word messed up my whole answer :/
thanks man!