Sum of infinite geometric series

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
6 replies · 4K views
motornoob101
Messages
45
Reaction score
0

Homework Statement


Homework Equations


The Attempt at a Solution



I don't get what I am doing wrong here, I have attached my solution below. The solution manual have their answer as 3e/(3-e). Thanks!
 

Attachments

  • Eqn001.gif
    Eqn001.gif
    957 bytes · Views: 578
Physics news on Phys.org
Try posting the question in LaTex from now on, attachments have to be approved and put extra load on the moderators.
 
Erm I don't think get it.. So I have e^(x-1) which is same as (e^x) (e^-1) and e^-1 is (1/e) no?
 
You have, skipping over your second term which simply makes no sense,
[tex]\frac{e^n}{3^{n-1}}= \frac{1}{e}\left(\frac{e}{3}\right)^{n-1}[/tex]
which is wrong- you have factored and e out of the numerator: it should be
[tex]\frac{e^n}{3^{n-1}}= e\left(\frac{e}{3}\right)^{n-1}[/tex]
 
Ohh I see. Thanks.