Giả sử \(\left|ã^2+bx+c\right|\ge\left|x^2-1\right|\) đúng với mọi số thực x. Chứng minh rằng \(\left|b^2-4ac\right|\ge4\)
Let a;b;c be positive real numbers such that \(a^2+b^2+c^2=\frac{1}{3}\). Prove that :
\(4\left(a+b+c\right)+\frac{2}{3}\left(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}\right)\ge10\)
Let \(a,b,c,k\) be positive real numbers such that \(k\left(ab+bc+ca\right)+2abc\le k^3\) . Prove that:
\(\left(1\right)k\left(a+b+c\right)\ge2\left(ab+bc+ca\right)\)
\(\left(2\right)k\left(a^3+b^3+c^3\right)\ge2\left(a^2b^2+b^2c^2+c^2a^2\right)\)
\(\left(3\right)k\left(a^{2n-1}+b^{2n-1}+c^{2n-1}\right)\ge2\left(a^nb^n+b^nc^n+c^na^n\right)\) \(\left(n\ge0;n\in R\right)\)
Find the values of a,b and c such that
\(\left(ax^2+bx+c\right)\left(x-1\right)=-5x^3+4x^2+3x-2\).
Answer: The values of a,b and c are ......... , respectively.
(used " ; " between the numbers)
Let a,b,c be positive numbers with abc = 1. Prove that
\(a^3+b^3+c^3+2\left[\left(ab\right)^3+\left(bc\right)^3+\left(ca\right)^3\right]\ge3\left(a^2b+b^2c+c^2a\right)\)
CMR nếu \(\frac{x}{a}=\frac{y}{b}=\frac{z}{c}\)thì \(\left(x^2+y^2+z^2\right).\left(a^2+b^2+c^2\right)=\left(ax+bx+cz\right)^2\)
Cho đa thứ \(f\left(x\right)=x\left(x+1\right)\left(x+2\right)\left(ax+b\right)\)xác định a, b để \(f\left(x\right)-f\left(x-1\right)=x\left(x+1\right)\left(2x+1\right)\)\(\forall x\)
Let \(a,b,c\ge0\) such that \(\left(a+b\right)\left(b+c\right)\left(c+a\right)\ne0\) . Prove that:
\(a^3+b^3+c^3+3abc-ab\left(a+b\right)-bc\left(b+c\right)-ca\left(c+a\right)\ge abc\left(\frac{2a}{b+c}+\frac{2b}{c+a}+\frac{2c}{a+b}-3\right)\)
Tìm a, b biết:
1./ \(x^4-3x+2=\left(x-1\right)\left(x^3+bx^2+ax-2\right)\)
2./ \(x^4+x^3-x-1=\left(x^2-1\right)\left(x^2+ax+b\right)\)
Giải hộ mình nha, mình cần gấp !
Xác định a,b,c để :
\(x^3-ax^2+bx-c=\left(x-a\right)\left(x-b\right)\left(x-c\right)\)