Violympic toán 9
Các câu hỏi tương tự
Cho a, b, c>0 và a+b+c=abc. CMR: \(\frac{b}{a^2}+\frac{c}{b^2}+\frac{a}{c^2}+3\ge\left(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}\right)^2+\sqrt{3}\)
Cho a,b,c 0. CMR:
1. a^3+b^3+c^3ge3abc
2. frac{x^2}{a}+frac{y^2}{b}gefrac{left(x+yright)^2}{a+b}
3. frac{x^2}{a}+frac{y^2}{b}+frac{z^2}{c}gefrac{left(x+y+zright)^2}{a+b+c}
4. a^4+b^4+c^4ge abcleft(a+b+cright)
5. frac{1}{left(a+1right)^2}+frac{1}{left(b+1right)^2}gefrac{1}{ab+1}
6.frac{1}{1+a^3}+frac{1}{1+b^3}+frac{1}{1+c^3}gefrac{3}{1+abc}
Đọc tiếp
Cho a,b,c > 0. CMR:
1. \(a^3+b^3+c^3\ge3abc\)
2. \(\frac{x^2}{a}+\frac{y^2}{b}\ge\frac{\left(x+y\right)^2}{a+b}\)
3. \(\frac{x^2}{a}+\frac{y^2}{b}+\frac{z^2}{c}\ge\frac{\left(x+y+z\right)^2}{a+b+c}\)
4. \(a^4+b^4+c^4\ge abc\left(a+b+c\right)\)
5. \(\frac{1}{\left(a+1\right)^2}+\frac{1}{\left(b+1\right)^2}\ge\frac{1}{ab+1}\)
6.\(\frac{1}{1+a^3}+\frac{1}{1+b^3}+\frac{1}{1+c^3}\ge\frac{3}{1+abc}\)
cho \(\left\{{}\begin{matrix}a,b,c>0\\a+b+c=abc\end{matrix}\right.\).CMR: \(\frac{b}{a^2}+\frac{c}{b^2}+\frac{a}{c^2}+3\ge\left(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}\right)^2+\sqrt{3}\)
(4)Bài 1:Với forall ab0. CMR: a+ frac{1}{bleft(a-bright)}ge3
(7) Bài 2: Cho a,b,c ne 0 .CMR: frac{a^2}{b^2}+frac{b^2}{c^2}+frac{c^2}{a^2}gefrac{b}{a}+frac{c}{b}+frac{a}{c}
(8) Bài 3: Cho a,b,c0 thõa mãn abc1
CMR: frac{b+c}{sqrt{a}}+frac{c+a}{sqrt{b}}+frac{a+b}{sqrt{c}}gesqrt{a}+sqrt{b}+sqrt{c}+3
Đọc tiếp
(4)Bài 1:Với \(\forall\) a>b>0. CMR: a+ \(\frac{1}{b\left(a-b\right)}\ge3\)
(7) Bài 2: Cho a,b,c \(\ne\) 0 .CMR: \(\frac{a^2}{b^2}+\frac{b^2}{c^2}+\frac{c^2}{a^2}\ge\frac{b}{a}+\frac{c}{b}+\frac{a}{c}\)
(8) Bài 3: Cho a,b,c>0 thõa mãn abc=1
CMR: \(\frac{b+c}{\sqrt{a}}+\frac{c+a}{\sqrt{b}}+\frac{a+b}{\sqrt{c}}\ge\sqrt{a}+\sqrt{b}+\sqrt{c}+3\)
Cho a, b \(\ge\)0. CMR: a3+b3\(\ge\)ab(a + b)
Áp dụng CM: \(\frac{1}{a^3+b^3+1}+\frac{1}{b^3+c^3+1}+\frac{1}{a^3+c^3+1}\le1\) với a, b, c > 0 thỏa mãn abc=1
Cho a,b,c>0 thoả mãn : a+b+c=3. CMR: \(\frac{1}{a^2+1}+\frac{1}{b^2+1}+\frac{1}{c^2+1}\ge\frac{3}{2}\)
Bài 1: Cho a,b,c \(\ge\)0. CMR: \(\frac{b+c}{a}+\frac{c+a}{b}+\frac{a+b}{c}\ge6\)
Bài 2: Cho a,b,c \(\ge\)0. CMR: \(\frac{a}{b+c}+\frac{b}{c+a}+\frac{c}{a+b}\ge\frac{3}{2}\)
Cho a,b,c 0 . Cmr :
a, a+b+frac{1}{4}≥sqrt{a+b}
b, ( a+b+ frac{1}{4})2 + ( b+c+frac{1}{4}) + ( c+a+frac{1}{4}) ≥ (frac{1}{frac{1}{a}+frac{1}{b}}+frac{1}{frac{1}{b}+frac{1}{c}}+frac{1}{frac{1}{c}+frac{1}{a}})
Đọc tiếp
Cho a,b,c > 0 . Cmr :
a, a+b+\(\frac{1}{4}\)≥\(\sqrt{a+b}\)
b, ( a+b+ \(\frac{1}{4}\))2 + ( b+c+\(\frac{1}{4}\)) + ( c+a+\(\frac{1}{4}\)) ≥ (\(\frac{1}{\frac{1}{a}+\frac{1}{b}}\)+\(\frac{1}{\frac{1}{b}+\frac{1}{c}}\)+\(\frac{1}{\frac{1}{c}+\frac{1}{a}}\))
cho a,b>0 cm\(\frac{1}{1+a^2}+\frac{1}{1+b^2}\ge\frac{2}{1+ab}\) nếu \(ab\ge1\)
b) cho a,b,c\(\ge\)1. CMR \(\frac{1}{1+a^4}+\frac{1}{1+b^4}+\frac{1}{1+c^4}\ge\frac{1}{1+ab^3}+\frac{1}{1+bc^3}+\frac{1}{1+ca^3}\)