Sucesiones y Series Geométricas

$$a_n = a_1 \cdot r^{n-1}$$

$$S_n = \frac{a_1(1 - r^n)}{1-r} (r\neq1)$$

$$S = \frac{a_1}{1-r}(|r|<1) \text{Serie geometrica infinita}$$