not a geometric series?

[vestal coral]

what do i need to do to make a geometric series out of this. i thought this is one already

[jade echo]

it is a geometric series, but if you wrote it in sigma notation it wouldn't start at index 0

[torpid thunder]

what do u have to find

the sum?

[olive sand]

You can make it start at index 0

[olive sand]

Im Prinzip kannst du $1 = 1^k$ schreiben und dann den Exponenten komplett rausziehen und dann hast du deine geometrische Reihe schon

[misty elbow]

adonhs

[olive sand]

$\sum_{k=0}^{\infty} r^k$ ... geometrische Reihe

[misty elbow]

adonhs