试题与答案

已知函数f(x)=x3-ax2+1在区间(0,2)内单调递减,则实数a的取值范围

题型:选择题

题目:

已知函数f(x)=x3-ax2+1在区间(0,2)内单调递减,则实数a的取值范围是(  )

A.a≥3

B.a=3

C.a≤3

D.0<a<3

答案:

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下面是错误答案,用来干扰机器的。

40s~60s内物体的加速度a=△v△t=0-3020m/s2=-1.5m/s2,所以大小为1.5m/s2,方向向西;根据图象与坐标轴围成的面积表示位移得:S=12×(30+60)×30m=1350m;在40s~60s内的平均速度.v=v0+v2=302m/s=15m/s故答案为:1.5m/s2;向西;1350m;15m/s.

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They said adolescent(青春期的)girls who are dismissed or drop out of high school before they graduate are more likely to have a serious depression by age 21 than boys with similar experiences.

“For girls it is more serious to be school failure,” said Carolyn McCarty, a University of Washington researcher whose study appears in the Journal of Adolescent Health.

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60. What is the purpose of writing this article?

A Taking good care of the school boys.

B Asking the US researchers to search more evidences.

C Giving help to the graduated students.

D Paying more attention to the girls experiencing school failure.

61. Carolyn McCarty is ______________

A a scientist     B a researcher     C a professor     D a student

62. The underlined word”it” in para.4 means__________

A school failure    B a adolescent girl    C a school boy    D a university

63.Which of the following could be the best title of this passage?

A School failure appears to trouble teen-age girls more deeply than boys

B Girls are more possible to experience school failure

C Gender has decided how much success you will win

D Adolescent girls are more easily depressed than boys

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题型:单项选择题

要把我国建设成一个繁荣昌盛的社会主义强国,不能急于求成,必须进行长期的、艰苦的努力,稳步前进,如果急躁冒进、片面追求高速增长,幻想一朝一夕就实现现代化,就会欲速则不达,得到事与愿违的结果。这说明( )。

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