函数z=z(x,y)由F(xy,z)=x-搜答案-大师作文网

y+y∂z/∂x+z+x∂z/∂x=0∂z/∂x=-(y+z)/(x+y)∂2z/∂x2=【∂

df/dx=f'(xy,yz,x-z)(y+y*dz/dx+1-dz/dx)=0(1-y)dz/dx=f'(xy,yz,x-z)*(y+1)dz/dx=f'(xy,yz,x-z)*(y+1)/(1-y

设u=xy,v=lnx+g(xy),则x(∂z/∂x)-y(∂z/∂y)=∂f/∂v.原因如下：dz=(∂f/

e^(-xy)-2z+e^z=0-ye^(-xy)-2z'(x)+e^zz'(x)=0z'(x)=ye^(-xy)/(e^z-2)-xe^(-xy)-2z'(y)+e^zz'(y)=0z'(y)=xe

e^y-e^x=xy两边求导,得e^y*y'-e^x=y+xy'(e^y-x)y'=(e^x+y)所以y'=(e^x+y)/(e^y-x)x=0时,e^y-e^0=0,则e^y=1,则y=0所以y'(

对方程两边求全微分得：(e^z-1)dz+y^3dx+3xy^2dy=0（方法和求导类似）移项,有dz=-(y^3dx+3xy^2dy)/(e^z-1)

e^z-z+xy^3=0偏z/偏x：z'e^z-z'+y^3=0y^3=z'(1-e^z)z'=y^3/(1-e^z)偏z/偏y:z'e^z-z'+3xy^2=0z'=3xy^2/(1-e^z)偏z/

z(x)+z(y)=-(f(x)+f(y))/f(z)f(x)=f1(1-z(x)-f2z(x))f(y)=-f1z(y)+f2(1-z(y))f(z)=-f1-f2所以z(x)+z(y)=1+z(x

z对x的偏导xy+yz+zx=1y＋yfx'+z+xfx'＝0z对y的偏导x＋z+yfy'＋xfy'＝0z对y的偏导1+fx'+yfxy"+fy'+xfxy"=01+(fx'+fy')+(x+y)fx

令G(X,Y,Z)=F(xy,z-2x)GZ'=F'2GX'=yF'1-2F'2∂z/∂x=-GX'/GZ'=(2F'2-yF'1)/F'2Gy'=xF'1∂z/&

两端对x求偏导得：-ye^(-xy)-2(z/x)+(z/x)e^z=0,所以,z/x=ye^(-xy)/(e^z-2)两端对y求偏导得：-xe^(-xy)-2(z/y)+(z/y)e^z=0,所以,

因为x、y都为自变量,不是宗量,故此题没有全微分,应只有偏微分.详解如下：对方程两边微分：左边：de^z=e^z*dz右边d[xyz+cos(xy)]=xydz+yzdx+xzdy-(sinxy)*(

y+y∂z/∂x+z+x∂z/∂x=0∂z/∂x=-(y+z)/(x+y)y∂2z/∂x2+2ͦ

z=f(x,y∧2,z)两边取全微分,dz=f'xdx+(f'y)*2ydy+f'zdz所以dz=[(f'x)/(1-f'z)]dx+[2y(f'y)/(1-f'z)]dy

再问：是否还能给出一种利用题目所给的条件(关于x,y,z的函数)去证明的方法吗？再答：这就是课本上隐函数求导公式的应用，你想得太多了，没有必要的！

1、隐函数对x求导得1+az/ax+yz+xy*az/ax=0,故az/ax=－(1+yz)/(1+xy)；F对x求导得aF/ax=e^x*y*z^2+e^x*y*2z*az/ax；当x＝0,y＝1时

令u=xy,v=e^(x+y)Z'x=Z'u*U'x+Z'v*V'x=f'u*y+f'v*e^(x+y)Z'y=Z'u*U'y+Z'v*V'y=f'u*x+f'v*e^(x+y)