【单选题】患者男性,41岁,浅昏迷2日,为患者行留置导尿最主要的目的是:
【单选题】以下关于零电势参考点的选取原则说法不正确的是 ( )
B.
零电势参考点的选取原则是要保证积分结果有物理意义,并且保证积分结果最简单.
C.
对于场源电荷是有限大的带电体,一般选取无穷远为零电势参考点.
D.
对于场源电荷是无限大的带电体,选取无穷远为零电势参考点是没有物理意义的.
【简答题】已知直线y= x与直线y=kx+b交于点A(m,n)(m>0),点B在直线y= x上且与点A关于坐标原点O成中心对称. (1)若OA=1,求点A的坐标; (2)若坐标原点O到直线y=kx+b的距离为1.94,直线y=kx+b与x轴正半轴交于点P,且△PAB是以PA为直角边的直角三角形,求点A的坐标.(sin15°=0.26,cos15°=0.97,tan15°=0.27)
【判断题】5) The second important step is to accept complete responsibility for what both parties did.
【判断题】The second important step is to accept complete responsibility for what both parties did.
【简答题】设O为坐标原点,曲线x 2 +y 2 +2x-6y+1=0上有两点P、Q,满足关于直线x+my+4=0对称,又满足·=0. (1)求m的值; (2)求直线PQ的方程.
【多选题】关于电势零点的选取,说法正确的是
B.
工程上常常选地为电势零点,认为地和无穷远等电势
【简答题】设直线y=kx+1与圆x 2 +y 2 +kx+my﹣4=0交于M,N两点,且M,N关于直线x+y=0对称,求不等式组 表示平面区域的面积.
【单选题】The second important contribution that Werner made to the study of coordination chemistry was the postulate that the bonds to the ligands were fixed in space and therefore could by the application of ...
【多选题】下列关于电势零点的选取说法中,正确的是( )