开罗口袋学院2破解版:分式计算!!!!(紧急啊 ~~~~~~要过程的)

来源:百度文库 编辑:高考问答 时间:2024/04/29 21:58:33
已知1/[n*(n+1)]=1/n-1/(n+1)
求2/(a^2-4a+3)+1/(a^2-7a+12)+3/(a^2+a-2)

2/(a^2-4a+3)
=2/[(a-1)(a-3)]
=1/(a-3)-1/(a-1)

1/(a^2-7a+12)
=1/[(a-3)(a-4)]
=1/(a-4)-1/(a-3)

3/(a^2+a-2)
=3/[(a+2)(a-1)]
=1/(a-1)-1/(a+2)

所以原式=1/(a-4)-1/(a+2).