解方程1/(x+1)(x+2)+1/(x+2)(x+3)+.+1/(x+2005)(x+2006)=1/2x+4012

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/02 11:03:46
解方程1/(x+1)(x+2)+1/(x+2)(x+3)+.+1/(x+2005)(x+2006)=1/2x+4012

解方程1/(x+1)(x+2)+1/(x+2)(x+3)+.+1/(x+2005)(x+2006)=1/2x+4012
解方程1/(x+1)(x+2)+1/(x+2)(x+3)+.+1/(x+2005)(x+2006)=1/2x+4012

解方程1/(x+1)(x+2)+1/(x+2)(x+3)+.+1/(x+2005)(x+2006)=1/2x+4012
1/(x+1)(x+2)+1/(x+2)(x+3)+.+1/(x+2005)(x+2006)
=1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)+.+1/(x+2005)-1/(x+2006)
=1/(x+1)-1/(x+2006)
=2005/(x+1)(x+2006)
即原式化为:2005/(x+1)(x+2006)=1/2(x+2006)
解得x=4009

左=1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)...
=1/(x+1)-1/(x+2006)
=右=1/2(x+2006)
(你是不是打错了?=1/(2x+4012)括号没打?)
所以2x+4012=3x+3
x=4009

1/(x+1)(x+2)+1/(x+2)(x+3)+......+1/(x+2005)(x+2006)=1/(2x+4012)
1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)+......+1/(x+2005)-1/(x+2006))=1/(2x+4012)
1/(x+1)-1/(x+2006)=1/(2x+4012)
2005/(x+1)(x+2006)=...

全部展开

1/(x+1)(x+2)+1/(x+2)(x+3)+......+1/(x+2005)(x+2006)=1/(2x+4012)
1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)+......+1/(x+2005)-1/(x+2006))=1/(2x+4012)
1/(x+1)-1/(x+2006)=1/(2x+4012)
2005/(x+1)(x+2006)=1/2(x+2006)
4010/(x+1)(x+2006)=1/(x+2006)
4010/(x+1)(x+2006)=x+1/(x+1)(x+2006)
所以4010=x+1
x=4009
注:1/(x+1)(x+2)+1/(x+2)(x+3)+......+1/(x+2005)(x+2006)
=1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)+......+1/(x+2005)-1/(x+2006)
=1/(x+1)-1/(x+2006)
=2005/(x+1)(x+2006)
公式:1/a(a+1)=1/a-1/(a+1)

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