$\lim\limits_{x \to 0}(1 - x)^{\frac{1}{x}}=$（　　）.

$y = \dfrac{2x^3+\sqrt{x}+4}{x}$，则$y'(1)=$（　　）.

曲线$y = x^3 + 5x - 2$的拐点是（　　）.