"若数列{an}的前n项和为Sn=an^2+bn+c,求证数列{an}为等差数列的充要条件是c=0"

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"若数列{an}的前n项和为Sn=an^2+bn+c,求证数列{an}为等差数列的充要条件是c=0"
"若数列{an}的前n项和为Sn=an^2+bn+c,求证数列{an}为等差数列的充要条件是c=0"

"若数列{an}的前n项和为Sn=an^2+bn+c,求证数列{an}为等差数列的充要条件是c=0"
若{an}是等差数列.那么an的前n项和Sn=d/2n^2+(a0-d/2)*n c=0
若c=0 an=Sn-Sn-1=2a*n+b-a
an-an-1=2a
因此等差

题目有问题 吧