SOLUTION: Find S11 for the geometric series 1+3+9+27+... Iv'e tried tn=3tn-1 and got t11=3^10 and ended up with 59,049.. I'm an online student and my homework is multiple choice, the option

Algebra ->  Sequences-and-series -> SOLUTION: Find S11 for the geometric series 1+3+9+27+... Iv'e tried tn=3tn-1 and got t11=3^10 and ended up with 59,049.. I'm an online student and my homework is multiple choice, the option      Log On


   



Question 303740: Find S11 for the geometric series 1+3+9+27+...
Iv'e tried tn=3tn-1 and got t11=3^10 and ended up with 59,049.. I'm an online student and my homework is multiple choice, the options are a)84,934 b)88,573
c) 93,198 d) 96,143
Can you help me? I'm not sure what I'm doing wrong or if I am using the wrong formula, help would definitelly be appreciated =]
Thanks, Rissa

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Find S11 for the geometric series 1+3+9+27+...
Iv'e tried tn=3tn-1 and got t11=3^10 and ended up with 59,049.. I'm an online student and my homework is multiple choice, the options are a)84,934 b)88,573
c) 93,198 d) 96,143
Can you help me? I'm not sure what I'm doing wrong or if I am using the wrong formula, help would definitelly be appreciated =]
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S11 = (1 - 3^11)/(1-3)
= (177147 - 1)/2
= 88573
http://www.math10.com/en/algebra/geometric-progression.html