Tính các giới hạn:
1) $\mathop {\lim }\limits_{x \to 2}$$\frac{\sqrt[3]{4x}-2}{x-2}$ 2) $\mathop {\lim }\limits_{x \to 0}$$\frac{\sqrt[3]{1-x}-1}{x}$ 3) $\mathop {\lim }\limits_{x \to 1}$$\frac{\sqrt[3]{x}-1}{\sqrt[3]{x-2}+1}$
4) $\mathop {\lim }\limits_{x \to 1}$ $\frac{\sqrt[3]{2x-1}-\sqrt[3]{x}}{\sqrt{x}-1}$ 5) $\mathop {\lim }\limits_{x \to 0}$$\frac{\sqrt[3]{x-1}+\sqrt[3]{x+1}}{\sqrt{2x+1}-\sqrt{x+1}}$
6) $\mathop {\lim }\limits_{x \to -1}$$\frac{\sqrt[3]{x}+x^2+x1}{x+1}$ 7) $\mathop {\lim }\limits_{x \to 8}$$\frac{\sqrt{9+2x}-5}{\sqrt[3]{x}-2}$
8) $\mathop {\lim }\limits_{x \to 0}$$\frac{\sqrt[n]{1+x}-1}{x}$ 9) $\mathop {\lim }\limits_{x \to 1}$ $\frac{\sqrt[m]{x}-1}{\sqrt[n]{x}-1}$