math
posted by Bob .
sorry for before it is my first time using this website and this is the real question
in a geometric series t1=23,t3=92 and the sum of all of the terms of the series is 62813. How many terms are in the series?

t1 = 23 > a = 23
t3 = 92 >ar^2 = 92
divide them
r^2 = 4
r = ± 2
sum(n) = a(r^n  1)/(r1) = 62813
If r = 2
23( 2^n  1)/(21) = 62813
2^n  1 = 2731
2^n = 2732
but ....
n has to be a whole number, since it stands for the number of terms
2732 is NOT a power of 2,
so even though you typed it again with a correction , the question is still flawed. 
Answer is 13 terms
Respond to this Question
Similar Questions

Algebra
Use the geometric sequence of numbers 1, 1/3, 1/9, 1/27… to find the following: Using the formula for the sum of the first n terms of a geometric series, what is the sum of the first 10 terms? 
Math....Please help I have a deadline for tonight!
Use the geometric sequence of numbers 1, 1/3, 1/9 , 1/27… to find the following: b) Using the formula for the sum of the first n terms of a geometric series, what is the sum of the first 10 terms? 
math
Hi. I'm having trouble with the summation of n from i=2 of ((2^ni)(2^n)). Any help would be greatly appreciated! the way I am reading the question you have i is going from 2 to n so there will be n1 terms using i = 2,3,4,..,n I get … 
math
in a geometric series t1=23,t3=92 and the sum of all of the terms of the series is 6813. How many terms are in the series 
math
in a geometric series t1=23,t3=92 and the sum of all of the terms of the series is 62813. How many terms are in the series 
Math.
The first term of a geometric series is 4 and the sum of the first three terms of the series is 64. Find the sum of the first eight terms of the series. 
Math
The first two terms in a geometric series is 12. The sum of the first three terms of the same series is 62. Determine the first four terms of the series. 
math
in a geometric series t1=23,t3=92 and the sum of all of the terms of the series is 62 813. how many terms are in the series? 
math help
the sum of the first two terms in a geometric series is 12. the sum of the first three terms of the same series is 62. determine the first four terms of the series. 
math help!!
the first term in a geometric series is 4 and the sum of the first three terms of the series is 64. find the sum of the first eight terms of the series.