A. $f_{1}^{\prime}-f_{2}^{\prime}+xyf_{11}^{\prime\prime}-\frac{y}{x^{2}}f_{22}^{\prime\prime}$
B. $f_{1}^{\prime}-\frac{1}{x}f_{2}^{\prime}+xyf_{11}^{\prime\prime}+\frac{y}{x^{3}}f_{22}^{\prime\prime}$
C. $yf_{1}^{\prime}-\frac{1}{x}f_{2}^{\prime}+xyf_{11}^{\prime\prime}-\frac{y}{x^{3}}f_{22}^{\prime\prime}$
D. $f_{1}^{\prime}-\frac{1}{x^{2}}f_{2}^{\prime}+xyf_{11}^{\prime\prime}-\frac{y}{x^{3}}f_{22}^{\prime\prime}$
设f具有二阶连续偏导数, =xf(x,dfrac (y)(x)), 求 dfrac ({partial )^2z}(partial xpartial y)
(3)已知函数 =f(xy,(e)^x+y) ,且f(x,y)具有二阶连续偏导数.则-|||-dfrac ({partial )^2z}(partial xpa
设=f((x)^3+(y)^2), 其中f具有二阶连续偏导数,则 dfrac ({partial )^2z}(partial {y)^2}=
[题目]设函数f w)具有二阶连续导数, =f((e)^xcos y)-|||-满足 dfrac ({partial )^2z}(partial {x)^2}+
11.设 =f((x)^2+(y)^2) ,其中f具有二阶导数,求 dfrac ({a)^2z}(d{x)^2} -dfrac ({partial )^2z}(
设 =f(x+y,xy), f具有一阶连续偏导数,求 dfrac (partial z)(partial x), dfrac (partial z)(parti
15.设函数 =f(x+y,(e)^xy), 其中f具有二阶连续偏导数,求 a^2/ax, dfrac ({sigma )^2z}(partial {{x)^2
5.设 =f(2x-y)+g(x,xy), 其中函数f(t)二阶可导,g(u,v)具有连续的-|||-二阶偏导数,求 dfrac ({a)^2z}(partia
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}
设 z=f(u,v) 具有二阶连续偏导数, =xv =dfrac (x)(y), 以u,v为新变量变换方程-|||-^2dfrac ({partial )^2z