1,\dfrac{1}{3},\dfrac{3}{5},\dfrac{15}{7},\dfrac{105}{9},()
A.18\dfrac{1}{13}
B.19\dfrac{1}{2}
C.34\dfrac{4}{11}
D.85\dfrac{10}{11}
>>>查看解析
将原数列进行反约分得到:\dfrac{1}{1},\dfrac{1}{3},,\dfrac{3}{5},\dfrac{15}{7},\dfrac{105}{9}其中分母有列为1,3,5,7,9,(11)为等差数列,分子列为1,1,3,15,105,(945)后项除以前项得到1,3,5,7,(9)为等差数列。故所求项为\dfrac{945}{11}=85\dfrac{10}{11}
故正确答案为D。