A.若{an}成等差数列,则{|an|}也成等差数列
B.若{|an|}成等差数列,则{an}也成等差数列
C.若存在自然数n,使2an+1=an+an+2,则{an}是等差数列
D.若{an}是等差数列,则对任意正整数n都有2an+1=an+an+2
A.若{an}成等差数列,则{|an|}也成等差数列
B.若{|an|}成等差数列,则{an}也成等差数列
C.若存在自然数n,使2an+1=an+an+2,则{an}是等差数列
D.若{an}是等差数列,则对任意正整数n都有2an+1=an+an+2
D