想问一道a level数学等比数学的题目：a geometric series has first term a and comm_英语解答

想问一道a level数学等比数学的题目：
a geometric series has first term a and common ratio r, where 0

人气：110 ℃　时间：2020-06-29 00:54:23

解答

Let the first term be a.
The sum fo the first 3 terms is a(1+r+r^2).
As 0