Question

已知数列{an}中,下列各式不能说明{an}是等差数列的是

Answer 1

D对A：an-a(n-1)=(2-3n)-[2-3(n-1)]=-3 是等差数列对B：a(n+1)-an=2 是等差数列对C：a(n+1)-an=an-a(n-1) 是等差数列...