(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

I'm told to evaluate the following to the thousandths place:

[tex]\infty[/tex]

[tex]\Sigma[/tex] 7*(0.35)^k

k=1

2. Relevant equations

We know that an infinite equation can be expressed as:

S_{[tex]\infty[/tex]}=(a_{1})/1-r^{n}

3. The attempt at a solution

The first term (a_{1}) is 7 and r=.35 so I can plug those into the above equation. I can see that we're doing something along the lines of:

7+7(.35)+7(.35^2)+7(.35^3)

However, there are two issues I'm having.

1) How do I plug in n when it's infinity?

2) In the non-infinite sum of geometric series problems I've worked where in the [tex]\Sigma[/tex] equation it's r^k versus the normal format of r^k-1 I had to modify the problem to make it k-1 and ended up multiplying the whole thing by r and then subtracting r from the whole thing... It was kind of crazy and I'm still not sure why and what happened.

Do I have to do something like that here?

How do I solve this equation?

Thank you for your time!

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# Homework Help: Infinite series without k-1

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