\lim_{x\rightarrow \infty }\frac{\sqrt[3]{(1+\frac{1}{\sqrt[5]{2}}+...+\frac{1}{\sqrt[5]{n}})^{2}}}{\sqrt[5]{(1+\frac{1}{\sqrt[3]{2}}+...+\frac{1}{\sqrt[3]{n}})^{4}}} @Tiến Phùng @Aki-chan e cảm ơn