数列{an}满足a1=32,an+1=an2-an+1(n∈N*),则m=1a1+1a2+…+1a2010的整数部分是( )A. 0B. 1C. 2D. 3
问题描述:
数列{an}满足a1=
,an+1=an2-an+1(n∈N*),则m=3 2
+1 a1
+…+1 a2
的整数部分是( )1 a2010
A. 0
B. 1
C. 2
D. 3
答
由题设知,an+1-1=an(an-1),∴1an+1−1=1an−1-1an,∴1an−1-1an+1−1=1an,通过累加,得m=1a1+1a2+…+1a2010=1a1−1-1a2011−1=2-1a2011−1.由an+1-an=(an-1)2≥0,即an+1≥an,由a1=32,得a2=74,∴a3=216...
答案解析:由题设知,an+1-1=an(an-1),从而可得
-1
an−1
=1
an+1−1
,通过累加,得m=1 an
+1 a1
+…+1 a2
=1 a2010
-1
a1−1
=2-1
a2011−1
,由an+1-an=(an-1)2≥0,即an+1≥an,可得a2011≥a2010≥a2009≥a3>2,从而可得0<1
a2011−1
<1,所以1<m<2,故可得m的整数部分.1
a2011−1
考试点:数列递推式.
知识点:本题考查数列的性质和应用,解题时要认真审题,注意挖掘题设中的隐含条件,合理地运用数列的递推式.