(1)设 $y= \dfrac {1- \sqrt {x}}{1 x}e^{ \sin ^{2}(2x 1)}$, 求$y'$.
(2)设 $y=x^{ \sin { \dfrac {1}{x}}}$, 求$y'$.
(3)设 $y=2^{ \arctan \dfrac {1-x^{2}}{1 x^{2}}}$, 求$y'$.
$\text{A.}$ 若 $\lim \limits _{x \rightarrow 0^{ }}f(x)=0$, 则 $\lim \limits _{x \rightarrow 0^{ }}f'(x)=0$
$\text{B.}$ 若 $\lim \limits _{x \rightarrow 0^{ }}f'(x)=0$, 则 $\lim \limits _{x \rightarrow 0^{ }}f(x)=0$
$\text{C.}$ 若 $\lim \limits _{x \rightarrow \infty }f(x)= \infty $, 则 $\lim \limits _{x \rightarrow \infty }f'(x)= \infty$
$\text{D.}$ 若 $\lim \limits {x \rightarrow \infty }f'(x)=A>0$, 则 $\lim \limits {x \rightarrow \infty }f(x)= \infty$