等差数列{an}的前n项和为Sn,且S3=6,a3=4,则公差d=______

等差数列{an}的前n项和为Sn,且S3=6,a3=4,则公差d=______.
2025-04-06 00:20:28
推荐回答(1个)
回答1:

∵S3=

3(a1+3)
2
=6,
∴a1+a3=4,
而a3=4,
∴a1=0,
∴d=
a3?1
2
=2.
故答案为 2.