问题
解答题
如果有理数a,b满足|ab-2|+(1-b)2=0,试求
|
答案
∵|ab-2|≥0,(1-b)2≥0,且|ab-2|+(1-b)2=0,
∴ab-2=0,且1-b=0,解得ab=2,且b=1,
把b=1代入ab=2中,解得a=2,
则
+1 ab
+1 (a+1)(b+1)
+…+1 (a+2)(b+2) 1 (a+2007)(b+2007)
=
+1 2
+1 3×2
+…+1 4×3 1 2009×2008
=(1-
)+(1 2
-1 2
)+(1 3
-1 3
)+…+(1 4
-1 2008
)1 2009
=1-
+1 2
-1 2
+1 3
-1 3
+…+1 4
-1 2008 1 2009
=1-1 2009
=
.2008 2009