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在等比数列中an大于0在等比数列中,an大于0,且a(n+2)=

2007-11-05 22:00:29南***
在等比数列中,an大于0,且a(n+2)=an+a(n+1),则该数列的公比q为同上!谢谢各位帮帮忙!!在等比数列中an大于0在等比数列中,an大于0,且a(n+2)=an+a(n+1),则该数列的公比q为同上!谢谢各位帮帮忙!!:an大于0 ==> q>0 a?

最佳回答

  • an大于0 ==> q>0 a(n+2)=an+a(n+1) ==> a1*q^(n+1)=a1*q^(n-1)+a1*q^n ==> q^2 -q -1 =0 ==> q =(1+根号5)/2
    2007-11-05 22:05:49
  • 很赞哦! (272)