设方程\({x^2} + {y^2} + {z^2} = 2Rx\)确定函数\(z=z(x,y)\)，则\( { { \partial z} \over {\partial x}}=\) A: \( { { \partial z} \over {\partial x}} = { { R +x} \over z}\) B: \( { { \partial z} \over {\partial x}} =- { { R +x} \over z}\) C: \( { { \partial z} \over {\partial x}} = { { R - x} \over z}\) D: \( { { \partial z} \over {\partial x}} =- { { R - x} \over z}\)

第2类拉格朗日方程表达式为____ 。 A: $\frac{{\rm{d}}}{{{\rm{d}}t}}\left( {\frac{{\partial T}}{{\partial {{\dot q}_k}}}} \right) - \frac{{\partial T}}{{\partial {q_k}}} = 0$ B: $\frac{{\rm{d}}}{{{\rm{d}}t}}\left( {\frac{{\partial T}}{{\partial {{\dot q}_k}}}} \right) - \frac{{\partial T}}{{\partial {q_k}}} = {Q_k}$ C: $\frac{{\rm{d}}}{{{\rm{d}}t}}\left( {\frac{{\partial T}}{{\partial {{\dot q}_k}}}} \right) + \frac{{\partial T}}{{\partial {q_k}}} = {Q_k}$ D: 以上都不对

Dead space like ventilation refer to () A: decrease<br/>of partial alveolar ventilation B: increase<br/>of partial alveolar VA/Q C: increase<br/>of partial alveolar ventilation D: decrease<br/>of partial alveolar VA/Q E: increase<br/>of anatomic shunt

\&#91;设z=z(x,y)是由方程f(cx-az,cy-bz)=0所确定的函数,则a\frac{\partial z}{\partial x}+b\frac{\partial z}{\partial y}=（）\&#93; A: a B: b C: c D: 0

79. Partial Inversion______

下列方程中表示常微分方程的是（ ）。 A: \({x^2} + {y^2} = a \) B: \(y'' = {x^2} + {y^2} \) C: \( { { {\partial ^2}u} \over {\partial {x^2}}} + { { {\partial ^2}u} \over {\partial {y^2}}} = 1\) D: \(y = \tan wx \)

\(已知u=e^{xyz},则\frac{\partial^3u}{\partial x\partial y\partial z}=(\,)\) A: \[(x^2y^2z^2+zyz+1)e^{xyz}\] B: \[(x^2yz^2+3zyz+1)e^{xyz}\] C: \[(x^2y^2z^2+3zyz+1)e^{xyz}\] D: \[(x^2y^2z^2+3zyz)e^{xyz}\]

信用证中关于运输：“Transshipment permitted, partial shipment allowed, but partial shipment of each item not allowed”的中文意思是( ）。

Partial loss or damage is never recoverable with FPA.

A counter-offer is virtually a partial rejection of the original offer.