在平面直角坐标系中,若a=(x,y+2),b=(x,y-2),且|a|+|b|=

题型:解答题

问题:

在平面直角坐标系中,若
a
=(x,y+2),
b
=(x,y-2),且|
a
|+|
b
|=8.
(1)求动点M(x,y)的轨迹C的方程;
(2)过点(0,3)作直线l与曲线C交于A、B两点,设
OP
=
OA
+
OB
,是否存在这样的直线l,使得四边形OAPB为矩形?若存在,求出直线l的方程,不存在,说明理由.
考点:圆锥曲线综合
题型:解答题

适宜采用塞因塞用法治疗的是

A.真实假虚证

B.真寒假热证

C.真热假寒证

D.真虚假实证

E.虚实夹杂证

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机动车辆保险中,如果保险车辆的保险金额低于投保时的新车购置价,发生部分损失按照( )计算赔偿修复费用。

A.保险金额

B.投保时的新车购置价

C.保险金额与投保时的新车购置价差额

D.保险金额与投保时的新车购置价比例

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细菌合成细胞组分和获得能量的基质主要为()

A.蛋白质

B.糖原

C.脂类

D.糖类

E.淀粉

题型:解答题

In the following essay, each blank has four choices. Choose the best answer and write down on the answer sheet.

A Web browser is simply a terminal emulator, designed to display text on a screen. The two essential differences between an ordinary terminal emulator and a Web browser are that the browser knows how to deal with (1) , and that it has a mechanism for (2) graphical files. Display text, display graphics, and (3) hyperlinks ——there’s 99 percent of the (4) value. That’s not to say that the manufacturers didn’t go all - out to attach a hyperactive efflorescence of useless capabilities onto their browsers. Remember when media channels in the browser were a big deal, instead of the clutter you can’t wait to delete from your favorites of bookmarks menu Remember when client -side Java applets were supposed to become the preferred (5) , for application development Remember frames and all their nasty side effects

5()

A.plane

B.plant

C.plate

D.platform

题型:解答题

下面有关数字信封的说法哪个是正确的()

A.数字信封可以保障发送的信息不被泄露

B.数字信封需要使用发送者的私钥

C.数字信封能够确认发送者的身份

D.数字信封需要使用发送者的公钥

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