Question

HELP

Answer 1

\[s=a+ar+ar^2+ar^3+...ar ^{n-1}\]
\[rs=ar+ar^2+a4^3+ar^4+...ar^\]

Answer 2

\[rs=ar+ar^2+ar^3+ar^4+...ar^n\]

Answer 3

\[s-rs=s(1-r)=a-ar^n\]

Answer 4

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