解答下列各题：（1）计算：|-2|-4sin60°+12；（2）化简：（-2x）

发布时间：2017-05-16 17:35 │ 来源：www.tikuol.com

题型：解答题

问题：

解答下列各题：
（1）计算：|-2|-4sin60°+

；
（2）化简：（-2x）²+（6x³-12x⁴）÷（3x²）；
（3）解方程：

x-2

=1．

考点：整式的加减乘除混合运算解分式方程特殊角三角函数值

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用方框中所给词的适当形式填空，使短文通顺、连贯。

wear although before drop we happy happen everyone that never

     A little girl thought that she was not as beautiful as other girls and that nobody liked her. So she
was always 1_____ and didn't like to talk to others. However, one day, her mother gave her a beautiful
hairclip. When she 2______ it, she looked much more beautiful than 3______. She decided to wear it
to school. 
     On her way to school she found that 4______ who saw her smiled at her. Most of her classmates
said "Hello" to her, but this 5______ happened before. She thought that the beautiful hairclip had brought
her them all. She was so happy about all of the wonderful things. 6______ she didn't tell her classmates
about her beautiful hairclip, they all wanted to know what had 7______ to her. 
     When she went back home after school, her mother asked her, "Do you know you 8______ your
hairclip? I found it by the door this morning." 
     She understood 9______ she hadn't worn the hairclip to school at all. 
     It is not important what we wear and how we look. The most important is how we think about 10______.

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[ ]

A.I变大　　　

B.I变小　　　

C.U变大　　

D.U变小

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某同学设计了一种测定风力的装置，其原理如图20所示，迎风板与一轻弹簧的一端Ｎ相连接，穿在光滑的金属杆上。弹簧是绝缘材料制成的，其劲度系数k=1300N/m，自然长度为Ｌ₀＝０.５m，均匀金属杆用电阻率较大的合金制成，迎风板面积Ｓ=0.5m²，工作时总是正对着风吹来的方向。电路中左端导线与金属杆Ｍ端相连，右端导线接在Ｎ点并可随迎风板在金属杆上滑动，且与金属杆接触良好。限流电阻的阻值Ｒ=1，电源的电动势Ｅ=12Ｖ，内阻r=0.5。合上开关，没有风吹时，弹簧处于原长，电压表示数为Ｕ₁=3.0Ｖ；如果某时刻由于风吹使迎风板向左压缩弹簧，电压表的示数为

Ｕ₂ =2.0V，求：

（１）金属杆单位长度的电阻；

（２）此时作用在迎风板上的风力。

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小柴胡汤与蒿芩清胆汤共有药物是（）

A．柴胡

B．青蒿

C．半夏

D．茯苓

E．人参

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电力系统各企业及事业单位，其内部热工计量仪表和装置的建档考核、检定、管理和计量人员考核工作，由（）执行。

A.电力部门自成体系

B.地方计量部门

C.省计量部门

D.全国计量部门

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