Question

What is the sum of a 11–term geometric series if the first term is 4 and the last term is 4,096?

Answer 1

im getting 8,188 is that right ?

Answer 2

The sum of a Gp is given by

\[S_n = a (\frac{r^n-1}{r-1})\]
S_n-->Sum of n terms
n-->no of terms from first term
r--->common ratio
a-->first term
The above formula is applicable for r>1 (which is in your case)


Also you need to know that any term of a GP can be expressed as
\[a_n = ar^{n-1}\]
a_n-->n th term of Gp
a-->first term

Now try the problem

Answer 3

i know how to slve it, but idk if im getting the right answer

Answer 4

You are getting the right answer :)

Answer 5

8,188?

Answer 6

http://www.google.com/search?q=%284%29%282^11-1%29&ie=utf-8&oe=utf-8&client=ubuntu&channel=fs

Answer 7

Yes , 8188. My calculation above in the link