Question

Consider the infinite geometric series
a. Write the first four terms of the series.
b. Does the series diverge or converge?
c. If the series has a sum, find the sum.

Answer 1

\sum_{n=-1}^{\infty} -4(1/3)^{n-1}

Answer 2

is this right for a. ?

1. -4(1/3)^(1-1) = -4 x 1 =-4
2. -4(1/3)^(2-1) = -4/3
3. -4(1/3)^(3-1) = -4/9
4. -4(1/3)^(4-1) = -4/27

Answer 3

b. ? The series converges.

Answer 4

and is this correct for c because i have a feeling its wrong?
sum= -4/(1-(1/3))=-4/(2/3)=-6