本文为大家介绍的GRE数学复习考点是“算术级数之和”。

新版GRE数学复习重要考点：Sum of Arithmetic Progression

The sum of n-numbers of an arithmetic progression is given by

                                    S=nx*dn(n-1)/2

where x is the first number and d is the constant increment.

example:

sum of first 10 positive odd numbers:10*1+2*10*9/2=10+90=100

sum of first 10 multiples of 7 starting at 7: 10*7+7*10*9/2=70+315=385

remember:

For a descending AP the constant difference is negative.

以上的内容大家一定要好好掌握，在考试的时候发挥出自己应有的水平。