

1/[tex]\frac{A_{n}^{4}}{A_{n+1}^{3}-C_{n}^{n-4}}\leq \frac{24}{23}[/tex]
2/[tex]C_{n-2}^{n-1}+C_{n+2}^{n}> \frac{5}{2}A_{n}^{2}[/tex]
3/ [tex]\frac{A_{n+1}^{4}}{C_{n-1}^{n-3}}< 14P_{n}[/tex][/QUOTE]
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2/[tex]C_{n-2}^{n-1}+C_{n+2}^{n}> \frac{5}{2}A_{n}^{2}[/tex]
3/ [tex]\frac{A_{n+1}^{4}}{C_{n-1}^{n-3}}< 14P_{n}[/tex][/QUOTE]
Giúp em với ạ