Question

What is the sum of the geometric sequence 8, -16, 32 … if there are 15 terms?

Answer 1

Here:

a = 8 and r = -2

And n= 15 here..

So use:

\[\large Sum = \frac{a(1 - r^n)}{(1 - r)}\]

Answer 2

Are you getting or not @sourpatchwatermelon

Answer 3

no not really. -2^15 = -32768 i know that. If that's how you're supposed to do it.

Answer 4

Yes I know that method only..

Answer 5

\[\large Sum = \frac{8(1 + 32768)}{3}\]

Solve this..

Answer 6

so 87,384?

Answer 7

@waterineyes did I get it right? or?

Answer 8

Well Done..

Yes you are right..

Answer 9

thanks