BasicSequence
AIME
Difficult
2016
For $-1 < r < 1$, let $S(r)$ denote the sum of the geometric series $$12+12r+12r^2+12r^3+\cdots .$$Let $a$ between $-1$ and $1$ satisfy $S(a)S(-a)=2016$. Find $S(a)+S(-a)$.
The solution for this problem is available for
$0.99.
You can also purchase a pass for all available solutions for
$99.