已知下列反应的平衡常数:<img src='https://img2.soutiyun.com/ask/2019-12-18/945528385312623.png' />则同温下反<img src='https://img2.soutiyun.com/ask/2019-12-18/945528393394473.png' />的平衡常数为( )。
设函数z=ysin(xy)+(1-y)arctanx+e<sup>-2y</sup>,则<img src='https://img2.soutiyun.com/latex/latex.action' />=( )
如下图所示,在△ABC中,已知AB=AC,AM=AN,∠BAN=30°。问∠MNC的度数是多少?()<img src='https://img2.soutiyun.com/shangxueba/ask/1737001-1740000/1737573/ct_gdxd11z_gdxmaths_00640(20096).jpg' />
设z是任一复数,证明<img src='https://img2.soutiyun.com/ask/2021-01-13/9794048514659.png' />
在图5-2-18所示大传动比减速器中,已知蜗杆1和5的线数z<sub>1</sub>=1,z<sub>5</sub>=1,且均为右旋。其余各轮齿数<img src='https://img2.soutiyun.com/ask/2021-01-24/980354984405348.png' />求传动比i<sub>1H</sub>。
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。
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。
已知f(0)=0,若<img src='https://img2.soutiyun.com/latex/latex.action' />,则f&39;(0)=( ).
由<img src='https://img2.soutiyun.com/latex/latex.action' />,确定可微函数z=z(x,y)(f也可微),则<img src='https://img2.soutiyun.com/latex/latex.action' />=( )
已知函数<img src='https://img2.soutiyun.com/latex/latex.action' />则下列结论中( )正确.
已知i为虚单位<img src='https://img2.soutiyun.com/shangxueba/ask/18162001-18165000/18164859/2015122210164736518.jpg' />,则z的实部为()。
设复数z满足<img src='https://img2.soutiyun.com/shangxueba/ask/1644001-1647000/1646297/ct_kgctem_kgctechoose_0132(106)1.jpg' />,则|1+z|=().
一个平面光波可以表示为E<sub>x</sub>=0,<img src='https://img2.soutiyun.com/ask/2020-02-10/950206088381301.png' />,E<sub>z</sub>=0,则( )。
图示截面对形心轴Z<sub>c</sub>的W<sub>zc</sub>有四种答案:()<img src='https://img2.soutiyun.com/shangxueba/ask/18996001-18999000/18996442/2016071913100889751.jpg' /><img src='https://img2.soutiyun.com/shangxueba/ask/18996001-18999000/18996442/2016071913100694430.jpg' />
电路如图题9-14所示,若Z<sub>L</sub>的实部、虚部均能变动,若使Z<sub>L</sub>获得最大功率,Z<sub>L</sub>应为何值,最大功率是多少?已知<img src='https://img2.soutiyun.com/ask/2020-08-28/967479719920724.png' />。
阻抗Z=4+j3Ω所加的电压有效值相量为<img src='https://img2.soutiyun.com/ask/2020-02-28/951757241815081.png' />,则其平均功率为( )。
求下列系统函数在10<|z|≤∞及0.5<|z|<10两种收敛情况下系统的单位样值响应,并说明系统的稳定性与因果性。<img src='https://img2.soutiyun.com/latex/latex.action' />
已知f(x)的原函数为<img src='https://img2.soutiyun.com/shangxueba/ask/18741001-18744000/18743910/2016071616173232033.jpg' />=()<img src='https://img2.soutiyun.com/shangxueba/ask/18741001-18744000/18743910/2016071616172745358.jpg' />
图示截面图形对形心轴z的惯性矩Iz= 。<img src='https://img2.soutiyun.com/shangxueba/ask/17052001-17055000/17054089/29d9665-chaoxing2016-412871.jpeg' />
地基压缩层的计算深度z应满足式<img src='https://img2.soutiyun.com/shangxueba/ask/18519001-18522000/18519169/201510300931081470.png' />,其中△s<img src='https://img2.soutiyun.com/shangxueba/ask/18519001-18522000/18519169/2015103009312055805.png' />′的意义是()。
一离散序列x(n),若其Z变换X(z)存在,而且X(z)的收敛域为:<img src='https://img2.soutiyun.com/shangxueba/ask/18120001-18123000/18120940/2016031711544777476.jpg' />,则x(n)为()。
一离散序列x(n),其定义域为-5n<<img src='https://img2.soutiyun.com/shangxueba/ask/18108001-18111000/18109006/2016031711571350484.jpg' />,若其Z变换存在,则其Z变换X(z)的收敛域为()。<img src='https://img2.soutiyun.com/shangxueba/ask/18108001-18111000/18109006/2016031711572938708.jpg' />
<img src='https://img2.soutiyun.com/ask/2021-01-10/979149524442748.png' />,Ω为圆锥面x<sup>2</sup>+y<sup>2</sup>=z<sup>2</sup>与平面z=1围成的区域.
<img src='https://img2.soutiyun.com/ask/2021-01-10/979149198516106.png' />其中Ω为由曲面z=xy和平面y=x,x=1,z=0围成的区域.