Question

I WILL GIVE YOU A MEDAL
Use the formula for the sum of the first n terms of a geometric sequence to solve. Find the sum of the first 8 terms of the geometric sequence: -8, -16, -32, -64, -128, . . . .

A. -2003

B. -2040

C. -2060

D. -2038

Answer 1

is the answer B or C yes or no?

Answer 2

use the formula

(A(1-r^n))/1-r

Answer 3

The n-th term of a geometric sequence with initial value 'a' and common ratio 'r' is given by:

a (base 'n') = a r ^ (n-1)

for e.g: Consider the following:
1, -3, 9, -27, 81, -243, ...

The common ratio 'r' = (-3/1) = -3
OR
= (81/-27) = -3

Answer 4

The n-th term of a geometric sequence with initial value 'a' and common ratio 'r' is given by:

a (base 'n') = a r ^ (n-1)

for e.g: Consider the following:
1, -3, 9, -27, 81, -243, ...

The common ratio 'r' = (-3/1) = -3
OR
= (81/-27) = -3

Answer 5

Plug in your terms...

Answer 6

Are you aware how to use the formula?

Answer 7

'a' TIMES (1-r^n)/(1-r)
a = -8
r = 2
n = 8

what do i do from here

Answer 8

-127/-1 ? or am i doing it wrong

Answer 9

okay your formula is