ans

023640
$y'=0$

019063
$y'=k$

040772
$2\mathrm{i}$

040773
$\{-4+3\mathrm{i}\}$

040774
$\pm\sqrt{2}\mathrm{i}$

040776
$-59$

040777
$\dfrac{6}{5}+\dfrac{2}{5}\mathrm{i}$

040778
$\cos 280^\circ+\mathrm{i}\sin 280^\circ$

040779
$-1-\sqrt{2}$

040780
$4+4\sqrt{3}\mathrm{i}$

040781
D

040783
A

040784
A

040785
(1) $190^\circ$; (2) $\theta-\dfrac{3\pi}{2}$; (3) $\dfrac{11}{6}\pi$; (4) $\pi+\arctan\dfrac{4}{5}$

040786
$\mathrm{i}$, $-\mathrm{i}$, $\dfrac{\sqrt{3}}{2}+\dfrac{1}{2}\mathrm{i}$, $-\dfrac{\sqrt{3}}{2}+\dfrac{1}{2}\mathrm{i}$, $\dfrac{\sqrt{3}}{2}-\dfrac{1}{2}\mathrm{i}$, $-\dfrac{\sqrt{3}}{2}-\dfrac{1}{2}\mathrm{i}$

040787
$\dfrac{1}{4}$或$\dfrac{7}{4}$

040789
$g(m)=\begin{cases}2\sqrt{9-m}, & m\le 0,\\ 6, & 0\le m\le 9, \\ 2\sqrt{m}, & m\ge 9\end{cases}$

040790
$-2$或$-1\pm \sqrt{5}$