等比數列求和 (無限項) | Summation of a Geometric Sequence (Sum to Infinity)

影片內容：

00:05 – 無限項之和的概念 | idea of sum to infinity
02:58 – 等比數列求和公式 (無限項) | derivation of the sum to infinity formula of geometric sequence
11:17 – 例子 1 | example 1
13:36 – 例子 2 | example 2
15:21 – 例子 3 | example 3