Question

Find S8 for the series -2 + -10 + -50 + -250 +...

Answer 1

first find r

Answer 2

just clarifying, s8 is the sum of the first 8 terms of the sequence? is what you gave us the sequence or the series?

divide each term by the one before it to find r

Answer 3

\[r=\frac{ -10 }{ -2 }=5\]

Answer 4

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

Answer 5

a=-2,r=5,n=8

Answer 6

-195312 should be the answer! i guuess!