Question

LAST QUESTION ! I PROMISE ! PLEASE HELP !

What is the sum of the geometric sequence 4, 12, 36 . if there are 9 terms?

Answer 1

find r then use the formula in finding the sum of geometric series...

r stands for the ratio of the first and the next term...

Answer 2

a1= 4 r=12/4=3

Answer 3

\[\Sigma = a\frac{1-r^n}{1-r}\]

Answer 4

\[a \left( \frac{ 1-r ^{n} }{ 1-r } \right)\]

a is the first term
r is the "common ratio" between terms
n is the number of terms

Answer 5

geometric sequence.... sorry for using the term 'series'

Answer 6

No, series is right

Answer 7

hahahnp !
now what am I supposed to do with that equation

Answer 8

substitute the values

Answer 9

You already know \(a\) and \(r\)/
\(n\) is the number of terms, 9.