Question

find the sum of the first six terms of the geometric sequence for which a2 = .7 and a3= .49

Answer 1

Common ratio \(\Large r = \frac{a_3}{a_2} = ?\)

Answer 2

.7

Answer 3

Yes. Find the first term a1 from 0.7 = a2 / a1 = .7 / a1

Answer 4

0?

Answer 5

0.7 = 0.7 / a1. a1 = 0.7 / 0.7 = 1.

Plug it into the formula for the sum of a geometric series.
a1 = 1; r = 0.7; n = 6

Answer 6

I got -5/.3 is that correct? @ranga

Answer 7

Sum = \[ a_1 * \frac{1-r^n}{1-r} = 1 * \frac{1-0.7^6}{1-0.7} = ?\]

Answer 8

2.94117

Answer 9

thank you, you are a life saver!!

Answer 10

Yes.