已知一列数a1,a2,a3,a4,a5,a6,a7,且a1=1,a7=729,a1/a2=a2/a3=a3/a4=a4/a5=a5/a6=a6/a7你能求出这列数吗
人气:338 ℃ 时间:2020-04-03 23:03:03
解答
由a1/a2=a2/a3=a3/a4=a4/a5=a5/a6=a6/a7,可知为等比数列
an=a1*q^(n-1)=q^(n-1)
a7=q^6=729=27^2
q=3
an=3^(n-1)
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