若两个等差数列{An},{Bn}的前n项和分别为An,Bn,且满足An/Bn=3n-1/(2n+3),则a13/b13=?
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若两个等差数列{An},{Bn}的前n项和分别为An,Bn,且满足An/Bn=3n-1/(2n+3),则a13/b13=?
若两个等差数列{An},{Bn}的前n项和分别为An,Bn,且满足An/Bn=3n-1/(2n+3),则a13/b13=?
若两个等差数列{An},{Bn}的前n项和分别为An,Bn,且满足An/Bn=3n-1/(2n+3),则a13/b13=?
a13/b13
=A(2*13-1)/B(2*13-1)
=A25/B25
=(3x5-1)/(2x25+3)
=74/53
备注:已知an,bn为等差数列,且前n项和为An,Bn,那么am/bm=A(2m-1)/B(2m-1).
公式不明白请追问哈