OSSD数学数列知识知多少？

　　等差数列与等比数列求和公式 　　大家好，今天我们来聊一下等差数列与等比数列求和公式的推导。 　　Derivation of Arithmetic Series Formula 等差数列求和公式的推导 　　When the mathematician Karl Gauss was eight years old, he used the following method to find the sum of the natural numbers from 1 to 100. 　　Let S100 represent the sum of the first 100 numbers. Wri…