函数f(x)=x2(x≤0)πsinx(0<x≤π),则集合{x|f[f(x)]

题型:选择题

问题:

函数f(x)=
x2(x≤0)
πsinx(0<x≤π)
,则集合{x|f[f (x)]=0}中元素的个数有(  )
A.2个B.3个C.4个D.5个
考点:集合间交、并、补的运算(用Venn图表示)函数的单调性、最值
题型:选择题

位于坐标原点的波源产生一列沿x轴正方向传播的简谐横波,波速v=40m/s,已知t=0时刻波刚好传播到x=13m处,部分波形图如图所示,则(     )

A.波源S开始振动的方向沿y轴正方向

B.t=0.45s时,x=9m处的质点的位移为5cm

C.t=0.45s时,波刚好传播到x=18m处

D.t=0.45s时,波刚好传播到x=31m处

题型:选择题

科学家目前正在求证一种仅由四个中子组成的微粒,这种微粒称为“四中子”。下列关于该微粒的说法正确的是(   )

A.呈电中性

B.带四个单位负电荷

C.带四个单位正电荷

D.质量数为2

题型:选择题

One day a few years ago a very funny thing happened to a neighbor of mine. He is a teacher at one of London’s big medical schools, He had finished his teaching for the summer term and was at the airport on his way to Russia to give a lecture.

He had put a few clothes and his lecture notes in his shoulder bag, but he had put Rupert, the skeleton (人体骨骼) to be used in his lecture, in a large brown suitcase (箱子). At the airport desk, he suddenly thought that he had forgotten to buy a newspaper. He left his suitcase near the desk and went over to the shop.

When he got back he discovered that someone had taken his suitcase by mistake. He often wonders what they said when they got home and found Rupert.

小题1:Who wrote the story?

A.Rupert’s teacher.

B.The neighbour’s teacher.

C.A medical school teacher.

D.The teacher’s neighbour.小题2: Why did the teacher put a skeleton in his suitcase?

A.He needed it for the summer term in London.

B.He needed it for the lecture he was going to give.

C.He wanted to take it to Russia for medical research.

D.He wanted to take it home as he had finished his teaching.小题3:What happened at the airport?

A.The skeleton went missing .

B.The skeleton was stolen .

C.The teacher forgot his suitcase.

D.The teacher took the wrong suitcase .小题4:Which of the following best tells the teacher’s feeling about the incident?

A.He is very angry .

B.He thinks it rather funny .

C.He feels helpless without Rupert.

D.He feels good without Rupert .

题型:选择题

下列症状中哪一项不是上颌骨或下颌骨骨折后都会出现的()

A.唇麻木

B.咬合错乱

C.骨折段移位

D.视觉障碍

E.影响呼吸

题型:选择题

下列关于类的说法中不正确的是( )。

A.类是同种对象的集合和抽象

B.类属于Java语言中的复合数据类型

C.类是Java程序中的基本的结构单位

D.类就是对象

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