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linh123658


Cho a,b,c là 3 số thực dương. Chứng minh:
$\frac{(b+c)^2}{a(b+c+2a)}+\frac{(a+c)^2}{b(a+c+2b)}+\frac{(a+b)^2}{c(a+b+2c)}$ \geq $2(\frac{a}{c+b}+\frac{b}{a+c}+\frac{c}{a+b})$
$\frac{(b+c)^2}{a(b+c+2a)}+\frac{(a+c)^2}{b(a+c+2b)}+\frac{(a+b)^2}{c(a+b+2c)}$ \geq $2(\frac{a}{c+b}+\frac{b}{a+c}+\frac{c}{a+b})$