- #1
oddjobmj
- 306
- 0
Homework Statement
I'm told to evaluate the following to the thousandths place:
[tex]\infty[/tex]
[tex]\Sigma[/tex] 7*(0.35)^k
k=1
Homework Equations
We know that an infinite equation can be expressed as:
S[tex]\infty[/tex]=(a1)/1-rn
The Attempt at a Solution
The first term (a1) 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!