cho\(\frac{a}{b-c}+\frac{b}{c-a}+\frac{c}{a-b}=0\)
Tinh M=\(\frac{a}{\left(b-c\right)^2}+\frac{b}{\left(c-a\right)^2}+\frac{c}{\left(a-b\right)^2}\)
cho\(\frac{a}{b-c}+\frac{b}{c-a}+\frac{c}{a-b}=0\)
Tinh M=\(\frac{a}{\left(b-c\right)^2}+\frac{b}{\left(c-a\right)^2}+\frac{c}{\left(a-b\right)^2}\)
CMR: Với mọi a,b,c>0
\(\frac{a^2}{b^2}+\frac{b^2}{c^2}+\frac{c^2}{a^2}=\frac{a}{b}+\frac{b}{c}+\frac{c}{a}+\frac{1}{b\left(b+c\right)}\left(a-b\right)^2+\frac{1}{c\left(c+a\right)}\left(b-c\right)^2+\frac{1}{a\left(a+b\right)}\left(c-a\right)^2\)
cho \(\frac{a}{b-c}+\frac{b}{c-a}+\frac{c}{a-b}=0.CMR:\frac{a}{\left(b-c\right)^2}+\frac{b}{\left(c-a\right)^2}+\frac{c}{\left(a-b\right)^2}=0\)
Cho a,b,c khác nhau.C/m
\(\frac{b-c}{\left(a-b\right)\cdot\left(a-c\right)}+\frac{c-a}{\left(b-c\right)\cdot\left(b-a\right)}+\frac{a-b}{\left(c-a\right)\cdot\left(c-b\right)}=\frac{2}{a-b}+\frac{2}{b-c}+\frac{2}{c-a}\)
1) Cho a, b, c > 0. Chứng minh: \(\left(\frac{a}{b}+\frac{b}{c}+\frac{c}{a}\right)^2\ge\left(a+b+c\right)\left(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}\right)\)
2) Cho \(a,b,c\in R\).
a) Chứng minh: \(\left(a^2+3\right)\left(b^2+3\right)\left(c^2+3\right)\ge4\left(a+b+c+1\right)^2\)
b) Chứng minh: \(\left(a^2+1\right)\left(b^2+1\right)\left(c^2+1\right)\ge\frac{5}{16}\left(a+b+c+1\right)^2\)
3) Cho \(a,b,c\in R\)Chứng minh: \(\frac{a^3}{b^2}+\frac{b^3}{c^2}+\frac{c^3}{a^2}\ge\frac{a^2}{b}+\frac{b^2}{c}+\frac{c^2}{a}\)
bđt<=>\(S_a\left(a-b\right)^2+S_b\left(b-c\right)^2+S_c\left(c-a\right)^2\ge0\)
with \(S_a=\frac{1}{2\left(a^2+b^2\right)}-\frac{c}{\left(a+b\right)\left(b+c\right)\left(c+a\right)}\)
\(S_b=\frac{1}{2\left(b^2+c^2\right)}-\frac{a}{\left(a+b\right)\left(b+c\right)\left(c+a\right)}\)
\(S_c=\frac{1}{2\left(c^2+a^2\right)}-\frac{b}{\left(a+b\right)\left(b+c\right)\left(c+a\right)}\)
cần cm \(S_a+S_c;S_b+S_c>0\)
lại có:\(S_a+S_c=\frac{1}{2}\left(\frac{1}{a^2+b^2}+\frac{1}{c^2+a^2}\right)-\frac{1}{\left(a+b\right)\left(c+a\right)}\)
\(>\frac{1}{2}\left(\frac{1}{\left(a+b\right)^2}+\frac{1}{\left(c+a\right)^2}\right)-\frac{1}{\left(a+b\right)\left(c+a\right)}>0\)
cmtt=>q.e.d
Cho a,b,c>0. CMR: \(\frac{a^4}{\left(a+b\right)\left(a^2+b^2\right)}+\frac{b^4}{\left(b+c\right)\left(b^2+c^2\right)}+\frac{c^4}{\left(c+a\right)\left(c^2+a^2\right)}\ge\frac{a+b+c}{4}\)
Hóng sol hay cho bài này.
Cho a,b,c >0. Chứng minh rằng: \(\frac{a}{b+c}+\frac{b}{c+a}+\frac{c}{a+b}\ge\frac{3}{2}+\frac{\left(9+4\sqrt{2}\right)\left(a-b\right)^2\left(b-c\right)^2\left(c-a\right)^2}{2\left(a+b\right)^2\left(b+c\right)^2\left(c+a\right)^2}\)
(tthnew)