等差数列中anan-1=n^2+3n+2,求其公差 注;n和n-1是a的下标
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等差数列中anan-1=n^2+3n+2,求其公差注;n和n-1是a的下标等差数列中anan-1=n^2+3n+2,求其公差注;n和n-1是a的下标等差数列中anan-1=n^2+3n+2,求其公差注
等差数列中anan-1=n^2+3n+2,求其公差 注;n和n-1是a的下标
等差数列中anan-1=n^2+3n+2,求其公差 注;n和n-1是a的下标
等差数列中anan-1=n^2+3n+2,求其公差 注;n和n-1是a的下标
anan-1=n^2+3n+2
a1a2=6
a3a2=12
a3/a1=2
a3=2a1
a1+a3=2a2
a2=3a1/2 d=a2-a1=a1/2
a1(3a1/2)=6
a1^2=4
a1=2 或 a1=-2
d=1 或 d=-1
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