设 z = e^u sin v，而 u = xy，v = x + y，则 (partial z)/(partial x) = ( )

设 z = (u)/(x+y)，而 u = e^xy，则 (partial z)/(partial y) = ()A. $\frac{xe^{xy}}{x+y}

设z=sin(uv)，u=x+y，v=x-y，则(partial z)/(partial y)=【】 设$z=\sin(uv)$，$u=x+y$，$v=x-y

若z=f(x,y),x=u+v,y=u-v,则(partial^2z)/(partial upartial v)=(partial^2z)/(partial x

设f(u)可导，z=xyf((y)/(x))，若x(partial z)/(partial x)+y(partial z)/(partial y)=xy(lny

sin (x+2y-3z)=x+2y-3z, 则 dfrac (partial z)(partial x)+dfrac (partial z)(partial

3.设 =sin (xy)+varphi (x,dfrac (x)(y)), 其中φ(u,v)具有二阶连续偏导数,求 dfrac ({partial )^2z}

已知函数z=f(xy,sin x+sin y)，f具有连续的偏导数，则(partial z)/(partial x)=(）A. $xf_1' + \cos x

5.设 sin (x+2y-3z)=x+2y-3z, 证明: dfrac (partial z)(partial x)+dfrac (partial z)(pa

殳 =(u)^2ln v =dfrac (y)(x), =2x-3y,-|||-则 dfrac (partial z)(partial y)= ()-|||-A

[例3](2007,数一)设f(u,v)为二元可微函数, =f((x)^y,(y)^x), 则 dfrac (partial z)(partial x)= __