Recent content by sammieh

thanks for your help!

O.K. I think I finally got it. Sn = 4, u1=1 and r=3x/2, so 4 = 1/(1-3x/2) solve for x and x = 1/2! FINALLY!

.5 ^ 2 = .25

yes it does. as we increased the exponent the answer kept getting closer and closer to 1.

o.k for example if we take r=.5 then as you increase the exponent r gets closer & closer to 1. right?

wouldn't r^n go to 1, but never reach 1 since it is always <1? and if r^n goes to 1 then wouldn't r^n-1 go to 0?

i'm still confused. Is the formula for an infinite sum: u1/r-1 ? and is the limit 1 as r goes to infinity?

o.k. n is the number of terms we are adding up. In our case infinity? Right?

o.k r is the constant common ratio and u1 is the first term of the series and I think n is a term in the series??

Is it something like Sn = u1(r^n – 1) ---------- where Sn is really S sub n and u1 is really u sub 1? r-1

it looks like things shifted when we wrote our problem. It should be the summation of (3x/2) raised to the r-1 power = 4 where r is going from 1 to infinity. I hope this makes sense to someone!

Help! We need to solve the following problem: ∞ r-1 find x if ∑ (3x/2) = 4 r=1 We know the answer is 1/2, but we have no idea how they got that answer. Can anyone help? Thanks, Sammie