SOLUTION: find the sum of the first eight terms in the series -4+8-16+…

Algebra ->  Sequences-and-series -> SOLUTION: find the sum of the first eight terms in the series -4+8-16+…      Log On


   

Question 860678: find the sum of the first eight terms in the series -4+8-16+…
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
S=t*(1 - r^n)/(1 - r)
r=-2
S=-4*(1 - (-2)^8)/(1 - (-2))
S = 340