Question

Find the sum of the terms of the finite geometric sequence 1, -2, 4, -8, ...,-8192.

Answer 1

a1=1, r=-2.

calculate which term (n=?) for an=-8192.

then use the formula for the sum

Answer 2

How do i find the sum?

Answer 3

I have sum of 2731 is correct?

Answer 4

Can't be that, since the sign of the last term determines the sign of the sum:

1
1-2 = -1
-1 + 4 = +3
3 - 8 = -5
-5 + 16 = +11
...

What did you get for n where An = -8192?