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uyenphuong8athd


cho a,b,c,d>0 c/m nếu $\dfrac{a}{b}$<1 thì$\dfrac{a}{b}$<$\dfrac{a+c}{b+c}$(1)
áp dụng c/m
a) 1<$\dfrac{a}{a+b}+\dfrac{b}{b+c}+\dfrac{c}{c+a}$<2
b) 1<$\dfrac{a}{a+b+c}+\dfrac{b}{b+c+d}+\dfrac{c}{c+d+a}+\dfrac{d}{d+b+a}$<2
c)2<$\dfrac{a+b}{a+b+c}+\dfrac{b+c}{b+c+d}+\dfrac{c+d}{c+d+a}+\dfrac{d+a}{d+a+b}$<3
Chú ý gõ latex
áp dụng c/m
a) 1<$\dfrac{a}{a+b}+\dfrac{b}{b+c}+\dfrac{c}{c+a}$<2
b) 1<$\dfrac{a}{a+b+c}+\dfrac{b}{b+c+d}+\dfrac{c}{c+d+a}+\dfrac{d}{d+b+a}$<2
c)2<$\dfrac{a+b}{a+b+c}+\dfrac{b+c}{b+c+d}+\dfrac{c+d}{c+d+a}+\dfrac{d+a}{d+a+b}$<3
Chú ý gõ latex
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