已知某个电路元件上的电压和电流为<img src="https://img2.soutiyun.com/ask/2020-07-07/96296750308178.png"/><img src="https://img2.soutiyun.com/ask/2020-07-07/962967514498434.png"/>求电压与电流的相位差。
久期分析是金融工具的利率敏感程度或利率弹性的直接衡量，其数学公式：<img src='https://img2.soutiyun.com/shangxueba/ask/1782001-1785000/1782627/ct_cjyhfxm_cjyhfxmchoose_00130(20096).jpg' />根据公式判断价格和收益率关系，下列说法正确的是()。
级数<img src='https://img2.soutiyun.com/latex/latex.action' />与∑<img src='https://img2.soutiyun.com/latex/latex.action' />满足u<sub>n</sub>≤v<sub>n</sub>(n=1，2，…)，则( )．
平面Ⅱ:2x-4y+3z-1=0与直线<img src='https://img2.soutiyun.com/latex/latex.action' />的位置关系是( )
若<img src='https://img2.soutiyun.com/latex/latex.action' />，<img src='https://img2.soutiyun.com/latex/latex.action' />，则下列式子成立的是( )
设连续型随机变量X的概率密度p(x)，则当( )时，<img src='https://img2.soutiyun.com/ask/2019-06-21/929983021545511.png' />称其为随机变量X的数学期望
直线<img src='https://img2.soutiyun.com/ask/2020-02-18/950884563792837.png' />与直线<img src='https://img2.soutiyun.com/ask/2020-02-18/950884577991765.png' />的关系是( )
若级数<img src='https://img2.soutiyun.com/latex/latex.action' />与<img src='https://img2.soutiyun.com/latex/latex.action' />分别收敛于S<sub>1</sub>与S<sub>2</sub>，则( )式未必成立．
用数学归纳法证明:<img src='https://img2.soutiyun.com/ask/2021-02-22/982838635749578.png' />
与数学式子<img src='https://img2.soutiyun.com/shangxueba/ask/1887001-1890000/1889652/ct_ctcbm_ctcbchoosej_05667(20093).jpg' />应的C语言表达式是
某控制信号的表达式为：<img src='https://img2.soutiyun.com/ask/uploadfile/3543001-3546000/fee733d2983209d7ec3ead91a0081ee2.jpg' />，图中()为该数学表达式的曲线图。
为人教版小学数学二年级下册第八单元《找规律》编写教学设计。<img src='https://img2.soutiyun.com/ask/uploadfile/10857001-10860000/9d76cec6ec9d0d9e9f3e8f38b4a89b57.jpg' /><img src='https://img2.soutiyun.com/ask/uploadfile/10857001-10860000/bf84b33a110c80e14c36aceafd8c9280.jpg' /><img src='https://img2.soutiyun.com/ask/uploadfile/10857001-10860000/4b532695d95dded62744dcea123eaa28.jpg' /><img src='https://img2.soutiyun.com/ask/uploadfile/10857001-10860000/52d76b825a40dfcc897fd05eabf42f75.jpg' />
某校对五年级100名同学进行学习兴趣调查，结果有58人喜欢语文，有38人喜欢数学，有52人喜欢外语。而且喜欢语文和数学(但不喜欢外语)的有6人，喜欢数学和外语(但不喜欢语文)的有4人，三科都喜欢的有12人，而且每人至少喜欢一科。有（）个同学只喜欢语文。<img src='https://img2.soutiyun.com/shangxueba/ask/3564001-3567000/3566020/20110215140237973.gif' />
有8本不同的书，其中数学书3本，英语书2本，科普书3本，将这8本书随机排在书架上，则3本数学书刚好放在一起且2本英语书刚好放在一起的概率有多大？（） A．<img src='https://img2.soutiyun.com/ask/uploadfile/4254001-4257000/f800427efc9bcb956dec2940c4957b52.jpg' />B．<img src='https://img2.soutiyun.com/ask/uploadfile/4254001-4257000/eb6e6cf2d383abfae47c57019595ad57.jpg' />C．<img src='https://img2.soutiyun.com/ask/uploadfile/4254001-4257000/60507f1b551e9925637bd20e4866b55a.jpg' />D．<img src='https://img2.soutiyun.com/ask/uploadfile/4254001-4257000/40cfa64357b04be09b7e6533ee05f61a.jpg' />
久期分析是金融工具的利率敏感程度或利率弹性的直接衡量，其数学公式：<img src='https://img2.soutiyun.com/shangxueba/ask/2625001-2628000/2626898/ct_cjyhfxm_cjyhfxmchoose_00130(20096).jpg' />根据公式判断价格和收益率关系，下列说法正确的是()。
假定其中的x的单位是角度且不考虑π值的精度，则与数学公式<img src='https://img2.soutiyun.com/shangxueba/ask/1662001-1665000/1664308/ct_cstccbm_ctccbchoose_00366(200912).jpg' />等价的C++语言表达式是
结合肺段模式肺动脉干与右肺动脉层面(如图)，选出右肺中叶的组成()<img src='https://img2.soutiyun.com/shangxueba/ask/17562001-17565000/17562091/2014060417141556038.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/17562001-17565000/17562091/2014060417143089113.jpg' />
过点M（3，-2，1）且与直线<img src='https://img2.soutiyun.com/shangxueba/ask/18729001-18732000/18730661/2016071514231735481.jpg' />平行的直线方程为（）<img src='https://img2.soutiyun.com/shangxueba/ask/18729001-18732000/18730661/2016071514234648431.jpg' />
下列化合物不能与<img src='https://img2.soutiyun.com/shangxueba/ask/17844001-17847000/17845710/2016032015180822263.jpg' />发生反应的是（）。<img src='https://img2.soutiyun.com/shangxueba/ask/17844001-17847000/17845710/2016032015181816392.jpg' />
一台4极中型异步电动机，P<sub>N</sub>=200kW，U<sub>N</sub>=380V,定子0联接，定子额定电流I<sub>N</sub>=385A,频率50Hz,定子铜耗<img src='https://img2.soutiyun.com/ask/2021-01-03/978560273352189.png' />=5.12kW.转子铜耗<img src='https://img2.soutiyun.com/ask/2021-01-03/978560286697952.png' />=2.85kW,铁耗<img src='https://img2.soutiyun.com/ask/2021-01-03/978560298531629.png' />=3.8kW，机械损耗<img src='https://img2.soutiyun.com/ask/2021-01-03/97856031340548.png' />=0.98kW，附加损耗<img src='https://img2.soutiyun.com/ask/2021-01-03/978560322980028.png' />=3kW，<img src='https://img2.soutiyun.com/ask/2021-01-03/978560339469971.png' />.正常运行时<img src='https://img2.soutiyun.com/ask/2021-01-03/978560353474772.png' />，起动时<img src='https://img2.soutiyun.com/ask/2021-01-03/978560375203015.png' />，由于磁路饱和与趋肤效应的影响，<img src='https://img2.soutiyun.com/ask/2021-01-03/978560441999835.png' /><img src='https://img2.soutiyun.com/ask/2021-01-03/97856039470213.png' />.试求:
患者，男，5岁，前牙反<img src='https://img2.soutiyun.com/shangxueba/ask/18504001-18507000/18505294/2015091816213562067.jpg' />，后牙近中错<img src='https://img2.soutiyun.com/shangxueba/ask/18504001-18507000/18505294/2015091816213562067.jpg' />，反覆<img src='https://img2.soutiyun.com/shangxueba/ask/18504001-18507000/18505294/2015091816213562067.jpg' />深，反覆盖小，牙齿无松动，牙列整齐，不伴拥挤。斜面导板斜面与牙体长轴所呈的角度为（）
自正中关系位能自如滑行至正中<img src='https://img2.soutiyun.com/shangxueba/ask/19008001-19011000/19008852/2015091014132537512.jpg' />，表明正中关系与正中<img src='https://img2.soutiyun.com/shangxueba/ask/19008001-19011000/19008852/2015091014132537512.jpg' />在（）。
烟气在加热炉回热装置中流动，拟用空气介质进行实验。已知空气黏度<img src='https://img2.soutiyun.com/shangxueba/ask/19014001-19017000/19015543/2016071910033856383.jpg' />，烟气运动黏度<img src='https://img2.soutiyun.com/shangxueba/ask/19014001-19017000/19015543/2016071910034077744.gif' />，烟气流速<img src='https://img2.soutiyun.com/shangxueba/ask/19014001-19017000/19015543/2016071910034354291.jpg' />，如若实际与模型长度的比尺λ<sub>L</sub>=5，则模型空气的流速应为：（）
在RLC串联电路中，电压与电流之间的相位差为<img src='https://img2.soutiyun.com/shangxueba/ask/2022-01/18/1118/20220118103755650.png' />，则<img src='https://img2.soutiyun.com/shangxueba/ask/2022-01/18/174/20220118103803306.png' />为()。
