设正整数m,n,满足m<n,且1/m2+m+1/(m+1)2+(m+1)+…+1/n2+n=1/23,则m+n的值是_.

问题描述:

设正整数m,n,满足m<n,且

1
m2+m
+
1
(m+1)2+(m+1)
+…+
1
n2+n
1
23
,则m+n的值是______.

1
n2+n
=
1
n
-
1
n+1

1
m2+m
+
1
(m+1)2+(m+1)
+…+
1
n2+n

=
1
m
-
1
m+1
+
1
m+1
-
1
m+2
+…+
1
n
-
1
n+1

=
1
m
-
1
n+1
=
1
23
=
22
23×22

∴m=22,n+1=23×22=506,n=505,
m+n=527.