

Nếu [tex]\frac{f(x)+f(y)}{2}\geq f(\frac{x+y}{2} )[/tex] (x, y>0)
thì [tex]\frac{f(x_{1})+f(x_{2})+...+f(x_{n})}{n}\geq f(\frac{x_{1}+x_{2}+...+x_n}{n}) (n\geq 2[/tex])
thì [tex]\frac{f(x_{1})+f(x_{2})+...+f(x_{n})}{n}\geq f(\frac{x_{1}+x_{2}+...+x_n}{n}) (n\geq 2[/tex])