Answer
$a_n = a_1 \cdot r^{n-1}$; Infinite sum $S_\infty = \frac{a_1}{1 - r}$ for $|r| < 1$.
Explanation
If $|r| \geq 1$, the infinite series diverges and has no finite sum.
Home / Library / ACT Mastery: English, Math, Reading & Science / Synthetic flashcard
What is the formula for the $n$-th term of a geometric sequence, and the sum of an infinite geometric series ($|r| < 1$)?
Study flashcard from the deck ACT Mastery: English, Math, Reading & Science.