Question

What is the sum of the first six terms of the geometric series 4 - 12 + 36 - . . . ?
Hint: Sn = a1(1 - r^n)/ 1-r, r = 1, where a1 is the first term and r is the common ratio.

Answer 1

so first you have to find the rate of change so work backwards.

Answer 2

Actually, you'll need the "common ratio," not the "rate of change.

Answer 3

so to find the common ratio you have to divide
soyour common ratio is 3