题目内容
已知函数f(x)=
,规定:
=f(
)+f(
)+f(
)+…+f(
) (n,m∈N•),且Snm=a1m+a2m+…+anm(n,m∈N•),则S20102010的值是
| x |
| 1+x |
| a | m n |
| 1 |
| n |
| 2 |
| n |
| 3 |
| n |
| m |
| n |
2020050
2020050
.分析:由题设知a1m=
+
+…+
,a2m=
+
+
+…+
,…anm=
+
+
+…+
,由此知S20102010=a12010+a22010+…+a20102010=(
+
+
+…+
)+(
+
+
+…+
)+…+(
+
+
+…+
),由此能求出其结果.
| 1 |
| 2 |
| 2 |
| 3 |
| m |
| m+1 |
| 1 |
| 3 |
| 1 |
| 2 |
| 3 |
| 5 |
| m |
| m+2 |
| 1 |
| n+1 |
| 2 |
| n+2 |
| 3 |
| n+3 |
| m |
| n+m |
| 1 |
| 2 |
| 2 |
| 3 |
| 3 |
| 4 |
| 2010 |
| 2011 |
| 1 |
| 3 |
| 1 |
| 2 |
| 3 |
| 5 |
| 2011 |
| 2012 |
| 1 |
| 2011 |
| 2 |
| 2012 |
| 3 |
| 2013 |
| 2010 |
| 4020 |
解答:解:∵函数f(x)=
,
=f(
)+f(
)+f(
)+…+f(
) (n,m∈N•),
∴a1m=f(1)+f(2)+…+f(m)=
+
+…+
,
a2m=f(
)+f(1)+f(
)+…+f(
)=
+
+
+…+
=
+
+
+…+
,
…
anm=f(
)+f(
)+f(
)+…+f(
)=
+
+
+…+
=
+
+
+…+
,
∵Snm=a1m+a2m+…+anm(n,m∈N•),
∴S20102010=a12010+a22010+…+a20102010
=(
+
+
+…+
)+(
+
+
+…+
)+…+(
+
+
+…+
)
=2020050.
故答案为:2020050.
| x |
| 1+x |
| a | m n |
| 1 |
| n |
| 2 |
| n |
| 3 |
| n |
| m |
| n |
∴a1m=f(1)+f(2)+…+f(m)=
| 1 |
| 2 |
| 2 |
| 3 |
| m |
| m+1 |
a2m=f(
| 1 |
| 2 |
| 3 |
| 2 |
| m |
| 2 |
| ||
1+
|
| 1 |
| 2 |
| ||
1+
|
| ||
1+
|
=
| 1 |
| 3 |
| 1 |
| 2 |
| 3 |
| 5 |
| m |
| m+2 |
…
anm=f(
| 1 |
| n |
| 2 |
| n |
| 3 |
| n |
| m |
| n |
| ||
1+
|
| ||
1+
|
| ||
1+
|
| ||
1+
|
=
| 1 |
| n+1 |
| 2 |
| n+2 |
| 3 |
| n+3 |
| m |
| n+m |
∵Snm=a1m+a2m+…+anm(n,m∈N•),
∴S20102010=a12010+a22010+…+a20102010
=(
| 1 |
| 2 |
| 2 |
| 3 |
| 3 |
| 4 |
| 2010 |
| 2011 |
| 1 |
| 3 |
| 1 |
| 2 |
| 3 |
| 5 |
| 2011 |
| 2012 |
| 1 |
| 2011 |
| 2 |
| 2012 |
| 3 |
| 2013 |
| 2010 |
| 4020 |
=2020050.
故答案为:2020050.
点评:本题考查数列和函数的综合运用,解题时要认真审题,寻找规律,注意合理地进行等价转化.
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