Question

Medal and Fan for someone who can check my answer!
What is the sum of the geometric sequence 8, -16, 32 . if there are 15 terms?

Answer 1

First term=a1=8..............r=-16/2=-2..........

..........a1(1-r^n)
S(n)=***********
...............1-r

............8(1-(-2)^(15))
S(15)=****************
...................1-(-2)

............8(1-(-2)^(15))
S(15)=****************
...................1+2

............8(1-(-2)^(15))
S(15)=****************
......................3.................. time

S(15)=87384..........ANSWER

Answer 2

that's correct

Answer 3

Okay, great. Thank you so much!