ans

008894
$[1,5)\cup (5,+\infty)$

002314
$(3,4)\cup (4,5)$

000271
$\dfrac{\sqrt{5}-1}2$

009823
最大值为$10$, 最小值为$2$

030483
$\pm 1$

002369
$\dfrac{x^2}{9/2}-\dfrac{y^2}{9/2}=1$

008910
B

003421
$\arccos \dfrac 13$

008912
$x^2-\dfrac{y^2}9=1$或$\dfrac{y^2}{81}-\dfrac{x^2}9=1$

030484
$90^{\circ}$

002391
(1) $y=x$($x>\sqrt{2}$或$y<-\sqrt{2}$); (2) $2x^2-y^2-4x+y=0$, 能取到每一个点

002435
(1) $y=\sqrt{3}x+1$; (2) $y=\dfrac{1+\sqrt{7}}2x+\dfrac{1-\sqrt{7}}2$或$y=\dfrac{1-\sqrt{7}}2x+\dfrac{1+\sqrt{7}}2$