<img src='https://img2.soutiyun.com/ask/2020-12-22/977495494038048.png' />，求S的r组合数。

如下图所示，<img src='https://img2.soutiyun.com/ask/2020-01-07/94725988610853.png' />应为( )。<img src='https://img2.soutiyun.com/ask/2020-01-07/947259894250194.png' />

已知两个线性变换<img src='https://img2.soutiyun.com/ask/2020-07-24/964447450539867.png' />，求从<img src='https://img2.soutiyun.com/ask/2020-07-24/964447482729708.png' />到<img src='https://img2.soutiyun.com/ask/2020-07-24/964447490132131.png' />的线性变换。

若函数<img src='https://img2.soutiyun.com/ask/2020-08-13/966178131180276.png' />,则<img src='https://img2.soutiyun.com/ask/2020-08-13/966178120045639.png' />。().此题为判断题(对，错)。

298K，下列反应的<img src='https://img2.soutiyun.com/latex/latex.action' />等于AgCl(s)的<img src='https://img2.soutiyun.com/latex/latex.action' />的为( )。

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( )

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( )

已知z=lnu，<img src='https://img2.soutiyun.com/latex/latex.action' />，则<img src='https://img2.soutiyun.com/latex/latex.action' />( )

面下部是指（）<img src='https://img2.soutiyun.com/shangxueba/ask/17523001-17526000/17524955/2015100717402331987.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/17523001-17526000/17524955/2015100717402599090.jpg' />

设<img src='https://img2.soutiyun.com/latex/latex.action' />则<img src='https://img2.soutiyun.com/latex/latex.action' />=( )．

男性，40岁，发现左侧颈部小包块，CT、MRI检查如图所示，请选择最可能的诊断（）<img src='https://img2.soutiyun.com/shangxueba/ask/18300001-18303000/18301269/2016072818164956119.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/18300001-18303000/18301269/2016072818165646074.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/18300001-18303000/18301269/2016072818170225050.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/18300001-18303000/18301269/20160728181708767.jpg' />

病历摘要：脑膜瘤患者女，55岁，视力下降数月。查体：视力下降，余神经体征阴性。<img src='https://img2.soutiyun.com/shangxueba/ask/21054001-21057000/21056152/2016080411361155670.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/21054001-21057000/21056152/2016080411363213140.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/21054001-21057000/21056152/2016080411363770796.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/21054001-21057000/21056152/2016080411364194722.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/21054001-21057000/21056152/2016080411364682394.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/21054001-21057000/21056152/2016080411365145350.jpg' />

女，3岁，右耳出生至今耳聋，结合图像，最可能的诊断是（）<img src='https://img2.soutiyun.com/shangxueba/ask/18597001-18600000/18599943/2015111217172541240.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/18597001-18600000/18599943/2015111217172661526.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/18597001-18600000/18599943/2015111217172726731.jpg' />

将函数f(x)＝x²在<img src='https://img2.soutiyun.com/shangxueba/ask/18735001-18738000/18737342/2016071617062459326.jpg' />上展开成余弦级数，其形式为<img src='https://img2.soutiyun.com/shangxueba/ask/18735001-18738000/18737342/2016071617063532608.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/18735001-18738000/18737342/2016071617065141640.jpg' />（）<img src='https://img2.soutiyun.com/shangxueba/ask/18735001-18738000/18737342/2016071617071375522.jpg' />

某一水泵的流量为<img src='https://img2.soutiyun.com/shangxueba/ask/18726001-18729000/18727196/20150618111622761.jpg' />，漏损流量为<img src='https://img2.soutiyun.com/shangxueba/ask/18726001-18729000/18727196/2015061811163167874.jpg' />，叶轮内的流量为<img src='https://img2.soutiyun.com/shangxueba/ask/18726001-18729000/18727196/2015061811163945969.jpg' />，则其容积效率<img src='https://img2.soutiyun.com/shangxueba/ask/18726001-18729000/18727196/2015061811164812800.jpg' />为（）。

如果把图示电路中的变压器视为理想器件，<img src='https://img2.soutiyun.com/shangxueba/ask/18774001-18777000/18774272/2016071815505494842.jpg' />时，（）。<img src='https://img2.soutiyun.com/shangxueba/ask/18774001-18777000/18774272/201607181551011369.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/18774001-18777000/18774272/2016071815510514617.jpg' />

利用上颌双侧<img src='https://img2.soutiyun.com/shangxueba/ask/17559001-17562000/17561302/2015093009262249313.jpg' />垫矫正反<img src='https://img2.soutiyun.com/shangxueba/ask/17559001-17562000/17561302/2015093009262249313.jpg' />，反<img src='https://img2.soutiyun.com/shangxueba/ask/17559001-17562000/17561302/2015093009262249313.jpg' />解除后<img src='https://img2.soutiyun.com/shangxueba/ask/17559001-17562000/17561302/2015093009262249313.jpg' />垫每次应磨去多少（）

一台4极中型异步电动机，P_N=200kW，U_N=380V,定子0联接，定子额定电流I_N=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:

设<img src='https://img2.soutiyun.com/shangxueba/ask/51291001-51294000/51293683/975264374908477.png' />是n维实向量,且<img src='https://img2.soutiyun.com/shangxueba/ask/51291001-51294000/51293683/975264387229182.png' />战性无关,<img src='https://img2.soutiyun.com/shangxueba/ask/51291001-51294000/51293683/975264401121976.png' /><img src='https://img2.soutiyun.com/shangxueba/ask/51291001-51294000/51293683/975264415373792.png' />是线性方程组

点（1，2，1）到平面<img src='https://img2.soutiyun.com/shangxueba/ask/19032001-19035000/19032905/2015110115113928560.png' />+2<img src='https://img2.soutiyun.com/shangxueba/ask/19032001-19035000/19032905/2015110115114815657.png' />+2<img src='https://img2.soutiyun.com/shangxueba/ask/19032001-19035000/19032905/2015110115115812967.png' />-10＝0的距离为（）。

有限长序列<img src='https://img2.soutiyun.com/shangxueba/ask/18120001-18123000/18120993/2016031714031255938.jpg' />=（）。<img src='https://img2.soutiyun.com/shangxueba/ask/18120001-18123000/18120993/2016031714041772379.jpg' />

可以直接利用模型上余留牙确定<img src='https://img2.soutiyun.com/shangxueba/ask/17538001-17541000/17540854/2015082211124147883.jpg' />关系的是（）。需要用<img src='https://img2.soutiyun.com/shangxueba/ask/17538001-17541000/17540854/2015082211124147883.jpg' />堤确定正中<img src='https://img2.soutiyun.com/shangxueba/ask/17538001-17541000/17540854/2015082211124147883.jpg' />位关系及垂直距离的是（）。需要用<img src='https://img2.soutiyun.com/shangxueba/ask/17538001-17541000/17540854/2015082211124147883.jpg' />堤确定正中<img src='https://img2.soutiyun.com/shangxueba/ask/17538001-17541000/17540854/2015082211124147883.jpg' />位关系和中线的是（）。需要用蜡<img src='https://img2.soutiyun.com/shangxueba/ask/17538001-17541000/17540854/2015082211124147883.jpg' />记录确定颌位记录的是（）。

女，19岁，发现左颈部无痛性肿块2年余，可活动，CT如图所示，最可能诊断为（）<img src='https://img2.soutiyun.com/shangxueba/ask/18291001-18294000/18291851/2016072817403713681.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/18291001-18294000/18291851/2016072817404619041.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/18291001-18294000/18291851/2016072817405389051.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/18291001-18294000/18291851/2016072817410029572.jpg' />

若<img src='https://img2.soutiyun.com/latex/latex.action' />，<img src='https://img2.soutiyun.com/latex/latex.action' />试证明时域卷积定理<img src='https://img2.soutiyun.com/latex/latex.action' />和频域卷积定理<img src='https://img2.soutiyun.com/latex/latex.action' />

男，4个月，相貌怪异，结合图像，最可能的诊断（）<img src='https://img2.soutiyun.com/shangxueba/ask/17796001-17799000/17798971/201511231032013640.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/17796001-17799000/17798971/2015112310320224881.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/17796001-17799000/17798971/201511231032042853.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/17796001-17799000/17798971/2015112310320644602.jpg' />

图示容器内盛有两种不同的液体，密度分别为<img src='https://img2.soutiyun.com/shangxueba/ask/17952001-17955000/17953624/2016031609491463375.jpg' />，<img src='https://img2.soutiyun.com/shangxueba/ask/17952001-17955000/17953624/2016031609492489129.jpg' />，则有（）。<img src='https://img2.soutiyun.com/shangxueba/ask/17952001-17955000/17953624/2016031609493123018.jpg' />