纯数1，3之后学什么纯数？——9231 进阶纯数1

纯数1，3之后学什么纯数？——9231 纯数1

-1.3 数列求和部分

use the method of differences to obtain the sum of a finite series -题目1(a)(b)

recognise, by direct consideration of a sum to

n

terms, when a series is convergent, and find the sum to infinity in such cases. -题目1(c)