r) [tex]\frac{a^3}{b(a+c)}+\frac{b}{2}+\frac{a+c}{4}\geq \frac{3}{2}a=>\frac{a^3}{b(a+c)}\geq \frac{3a}{2}-\frac{b}{2}-\frac{a+c}{4}[/tex]
tương tự => đpcm
p ) [tex]\sqrt{3+4^x}+\sqrt{3+4^y}+\sqrt{3+4^z}\geq \sqrt{(3\sqrt{3})^2+(4^{\frac{x}{2}}+4^{\frac{y}{2}}+4^{\frac{z}{2}})^2}\geq \sqrt{27+(3\sqrt[3]{4^{\frac{x}{2}+\frac{y}{2}+\frac{z}{2}}})^2}=\sqrt{27+9}=6[/tex]
o ) [tex](1+x)(1+\frac{y}{x})(1+\frac{9}{\sqrt{y}})^2\geq (1+x)(\frac{(1+\sqrt{y})^2}{1+x})(\frac{16^2}{\left (1+\sqrt{y} \right )^2})=256[/tex]
[TẶNG BẠN] TRỌN BỘ Bí kíp học tốt 08 môn
