在等差数列｛an}中,a1×a3=8,a2=3,则公差d=
人气：234 ℃ 时间：2019-10-24 08:47:54
解答
a1=a2-d=3-d
a3=a2+d=3+d
a1*a3=(3-d)(3+d)=8
9-d^2=8
d^2=1
d=(+/-)1
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