纺织棉多少钱一吨:初二数学

来源:百度文库 编辑:查人人中国名人网 时间:2024/04/27 03:15:39
若abc=1,求证[1/(ab+a+1)]+[1/(bc+b+1)]+[1/(ca+c+1)]=1要过程
看不懂哦~~~~~

1/(bc+b+1)=1/[(1/a)+b+1]=a/(ab+a+1)
1/(ca+c+1)=1/[(1/b)+(1/ab)+1]=ab/(ab+a+1)
原式左=[1/(ab+a+1)]+[a/(ab+a+1)]+[ab/(ab+a+1)]=(ab+a+1)/(ab+a+1)=1

[1/(ab+a+1)]+[1/(bc+b+1)]+[1/(ca+c+1)]
=1/(ab+a+1)+(1*a)/((bc+b+1)*a)+(1*ab)/((ca+c+1)*ab)
=1/(ab+a+1)+a/(ab+a+1)+ab/(ab+a+1)
=(ab+a+1)/(ab+a+1)
=1