一道数学题:x/(1*2)+x/(2*3).+x/(2008*2009)=2008

问题描述:

一道数学题:x/(1*2)+x/(2*3).+x/(2008*2009)=2008

(1-1/2+1/2-1/3+……+1/2008-1/2009)x=2008
2008/2009*x=2008
x=2009

左式=x[1/(1*2)+1/(2*3)+…+1/(2008*2009)]
=x[(1-1/2)+(1/2-1/3)+(1/3-1/4)+…+(1/2008-1/2009)]
=x(1-1/2009)=右式=2008
x=2009