정답
$a_n = a_1 \cdot r^{n-1}$; Infinite sum $S_\infty = \frac{a_1}{1 - r}$ for $|r| < 1$.
해설
If $|r| \geq 1$, the infinite series diverges and has no finite sum.
홈 / 라이브러리 / ACT Mastery: English, Math, Reading & Science / AI 플래시카드
What is the formula for the $n$-th term of a geometric sequence, and the sum of an infinite geometric series ($|r| < 1$)?
덱 'ACT Mastery: English, Math, Reading & Science'의 플래시카드.