

Cho abc khác 0 và (a+b)(b+c)(c+a)=8abc.CMR
[tex]\frac{a}{a+b}+\frac{b}{b+c}+\frac{c}{c+a}=\frac{3}{4}+\frac{ab}{(a+b)(b+c)}+\frac{bc}{(b+c)(c+a)}+\frac{ca}{(a+c)(a+b)}[/tex]
[tex]\frac{a}{a+b}+\frac{b}{b+c}+\frac{c}{c+a}=\frac{3}{4}+\frac{ab}{(a+b)(b+c)}+\frac{bc}{(b+c)(c+a)}+\frac{ca}{(a+c)(a+b)}[/tex]