一道八年级下册分式探究题观察下列等式 1/1*2=1-1/2,1/2*3=1/2-1/3,1/3*4=1/3-1/4将以上三个等式两边分别相加得1/1*2+1/2*3+1/3*4=1-1/2+1/2-1/3+1/3-1/4=1-1/4=3/4探究并计算1/2*4+1/4*6+1/6*8+.+1/2006*2008

问题描述:

一道八年级下册分式探究题
观察下列等式 1/1*2=1-1/2,1/2*3=1/2-1/3,1/3*4=1/3-1/4
将以上三个等式两边分别相加得1/1*2+1/2*3+1/3*4=1-1/2+1/2-1/3+1/3-1/4=1-1/4=3/4
探究并计算1/2*4+1/4*6+1/6*8+.+1/2006*2008

1/2*4+1/4*6+1/6*8+。。。。。。+1/2006*2008
=(1/4)(1/1*2+1/2*3+1/3*4...+1/1003*1004
=(1/4)(1-1/2+1/2-1/3+1/3...1/1003-1/1004)
=(1/4)(1-1/1004)
=(1/4)*1003/1004
=1003/4016

原式=1/2(1/2-1/4+1/4-1/6+....-1/2008)
=1/2*(1/2-1/2008)
=1003/4016

1/2*4+1/4*6+1/6*8+····+1/2006*2008
=(1/2-1/4+1/4-1/6+1/6-1/8+……+1/2006-1/2008)/2
=(1/2-1/2008)/2
=1003/4016