Question

What is the sum of the first five terms of the geometric sequence in which a1=3 and r=1/3????????

Answer 1

There's a formula for that. Hint: if you were to add up an infinite number of terms of this geometric sequence, the sum of all of those terms would be S= a /(1-r), where a is the first term of your sequence and r is the common multiple.

The formula for the sum of the first n terms resembles this formula for S, but is slightly different. Do you have access to a reference that might list that formula?

Answer 2

No

Answer 3

Is it 5/1-1/3

Answer 4

@mathmale

Answer 5

Please look up the following:

http://www.purplemath.com/modules/series5.htm

this article presents a formula for finding the first n terms of a geometric sequence.

Once again, the sum of an infinite (very large) number of terms of a geom. seq. is \[S=\frac{ a }{ 1-r }\] so this gives you a clue regarding what to look for. Would you please take a look at that web page?

Answer 6

Please note that a (the first term) and r (the common ratio) are given, and that you are to find the sum of the first 5 terms of this geom. sequence.

Answer 7

What is the first term? type it in here, please.

Answer 8

So s5

Answer 9

The first term is 3

Answer 10

S5=3/1-1/3

Answer 11

Is that correct @mathmale