原方程可化为:
[1-1 2
+1 3
?1 3
+1 5
?1 5
]+1 7
=1 (2n?1)(2n+1)
10 21
+3 7
=1 (2n?1)(2n+1)
10 21
=1 (2n?1)(2n+1)
1 21
(2n-1)(2n+1)=21
4n2=22
n2=
11 2
n1=
,n2=?
22
2
.
22
2
经检验n1=
,n2=?
22
2
22
2