一、伪等差数列和伪等比数列的定义1.伪等差数列如果一个数列从第二项开始,每一项与后一项的差大于等于(小于等于)同一个常数,那么这个数列就叫做伪等差数列,这个常数叫做伪等差数列的伪公差d.a_(n+1)-a_n≥d,a_n≥a_1+(n-1)d(1)a_(n+1)-a_n≤d,a_n≤a_1+(n-1)d(2) First, the pseudo-difference between the number of columns and pseudo-equivalence series definition 1. Pseudo-difference series If a series from the second, each with a difference greater than or equal to (less than or equal to) the same constant, then this series Is called the pseudo-difference series, this constant is called the pseudo-differential sequence pseudo-tolerance d.a_ (n + 1) -a_n≥d, a_n≥a_1 + (n-1) d (1) a_ (n + 1) -a_n ≤d, a_n≤a_1 + (n-1) d (2)