若,abc=1,求证,1/(ab+a+1)+1/(bc+b+1)+1/(ac+c+1)=1

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若,abc=1,求证,1/(ab+a+1)+1/(bc+b+1)+1/(ac+c+1)=1
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若,abc=1,求证,1/(ab+a+1)+1/(bc+b+1)+1/(ac+c+1)=1
若,abc=1,求证,1/(ab+a+1)+1/(bc+b+1)+1/(ac+c+1)=1

若,abc=1,求证,1/(ab+a+1)+1/(bc+b+1)+1/(ac+c+1)=1
abc=1
1/c=ab
a/(ab+a+1)+b/(bc+b+1)+c/(ac+c+1)
=a/(ab+a+1)+ab/(abc+ab+a)+1/(a+1+1/c)
=a/(ab+a+1)+ab/(ab+a+1)+1/(ab+a+1)
=1
abc=1
1/(ab+a+1)+1/(bc+b+1)+1/(ca+c+1)
=1/(ab+a+1)+a/(abc+ab+a)+ab/(abca+abc+ab)
=1/(ab+a+1)+a/(1+ab+a)+ab/(a+1+ab)
=(ab+a+1)/(ab+a+1)
=1

abc=1
所以
a=1/bc
ab=1/c
ac=1/b
所以原式=1/(1/c+1/bc+1)+1/(bc+b+1)+1/(1/b+c+1)
第一个分子分母同乘以bc,第三个分子分母同乘以b
=bc/(bc+b+1)+b/(bc+b+1)+1/(bc+b+1)
=(bc+b+1)/(bc+b+1)
=1

左边=abc/(ab+a+abc)+1/(bc+b+1)+1/(ac+c+1) ......第一个式子约a
=bc/(b+1+bc)+1/(bc+b+1)+1/(ac+c+1)
=(bc+abc)/(b+bc+abc)+1/(ac+c+1).....把第一个和第二个式子里面的1换成abc 这样就可以约去b
=(c+ac)/(1+c+ac)+1/(ac+c+1)
=1

1/(bc+b+1)=a/(abc+ab+a)=a/(ab+a+1)
1/(ac+c+1)=ab/(a²bc+abc+ab)=ab/(ab+a+1)
所以1/(ab+a+1)+1/(bc+b+1)+1/(ac+c+1)=(1+a+ab)/(ab+a+1)=1

原式=1/(ab+a+1)+a/(abc+ab+a)+b/(abc+bc+b)
=1/(ab+a+1)+a/(ab+a+1)+b/(1+bc+b)
=1/(ab+a+1)+a/(ab+a+1)+ab/(a+abc+ab)
=(1+a+ab)/(1+a+ab)=1

∵abc=1
∴1/(ab+a+1)+1/(bc+b+1)+1/(ac+c+1)
= 1/(ab+a+abc)+1/(bc+b+1)+1/(ac+c+1)
=1/[a(bc+b+1)]+1/(bc+b+1)+1/(ac+c+1)
=(a+1)/[a(bc+b+1)]+1/(ac+c+1)
=(a+1)/[a(bc+b+abc)]+1/(ac+c+1)

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∵abc=1
∴1/(ab+a+1)+1/(bc+b+1)+1/(ac+c+1)
= 1/(ab+a+abc)+1/(bc+b+1)+1/(ac+c+1)
=1/[a(bc+b+1)]+1/(bc+b+1)+1/(ac+c+1)
=(a+1)/[a(bc+b+1)]+1/(ac+c+1)
=(a+1)/[a(bc+b+abc)]+1/(ac+c+1)
=(a+1)/[ab(ac+c+1)]+1/(ac+c+1)
=(a+1)/[ab(ac+c+1)]+ab/[ab(ac+c+1)]
=(a+ab+1)/[ab(ac+c+1)]
=(a+ab+1)/(aabc+abc+ab)
=(a+ab+1)/(a+1+ab)
=1
也可以分子分母同乘a或b或c

收起

∵abc=1
∴ a=1/bc
ab=1/c
ac=1/b
∴ 原式=1/(1/c+1/bc+1)+1/(bc+b+1)+1/(1/b+c+1)
第一个分子分母同乘以bc,第三个分子分母同乘以b
=bc/(bc+b+1)+b/(bc+b+1)+1/(bc+b+1)
=(bc+b+1)/(bc+b+1)
=1