已知函数z=ex y,求全微分dz=
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1.3y²zdy+y³dz=cosxdx-e^xdz整理:(y³+e^z)dz=cosxdx-3y²zdydz=[cosx/(y³+e^z)]dx-[
第一题,参照二元隐函数对数求导法,将z^x=y^z变形,得xlnz=zlny下面就是求微分的一般方法了:lnzdx+(x/z)dz=lnydz+(z/y)dy移项化简:dz=(z^2dy-yzlnzd
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
因为z=z(x,y),所以全微分是dz=P(x,y)dx+Q(x,y)dy的形式,其中P(x,y)=∂z/∂x,Q(x,y)=∂z/∂y等式两边同时对x
dz=d(xyln(xy))=xyd(ln(xy))+ln(xy)d(xy)=xyd(xy)/(xy)+ln(xy)d(xy)=d(xy)+ln(xy)d(xy)=(1+ln(xy))d(xy)=(1
x^2+y^2+z^2+4z=02xdx+2ydy+2zdz+4dz=0(2z+4)dz-2xdx-2ydydz=(-2xdx-2ydy)/(2z+4)
设F(x,y,z)=z^2-2xyz-1则Fx=-2yz,Fy=-2xz,Fz=2z-2xyαz/αx=-Fx/Fz=-(-2yz)/(2z-2xy)=yz/(z-xy)αz/αy=-Fy/Fz=xz
Zxe^z=YZ+XYZx,Zx=YZ/(e^z-XY)Zy=XZ/(e^z-XY)dZ=Zxdx+Zydy=(ydx+xdy)Z/(e^z-xy)再问:设F(x,y,z)=e^z-xyzə
dz=(δz/δx)dx+(δz/δy)dy;δz/δx=f'*[δ(x/y)/δx]=f'*[(1/y)δx/δx]=f'/y;δz/δy=f'*[δ(x/y)/δy]=f'*[xδ(1/y)/δy
偏z/偏x=1/2根号(1-x^2-y^2)×(-2x)偏z/偏y=1/2根号(1-x^2-y^2)×(-2y)所以dz=[1/2根号(1-x^2-y^2)×(-2x)]dx+[1/2根号(1-x^2
zx=[√(x²+y²)-x²/√(x²+y²)]/(x²+y²)=y²/(x²+y²)^(3/2)
zx=1/y,代入y=1得zx=1zy=-(x/y^2)代入x=2,y=1得zy=-2所以dz=dx-2dy
dz=(y+y/(X^2))dx+(x-1/x)dy,
dz/dx=1/y,在(2,1)的值是1dz/dy=-x/y^2,在(2,1)的值是-2所以dz|(2,1)=dx-2dy
zx=1/(1+(x/y)²)*1/y=y/(x²+y²)zy=1/(1+(x/y)²)*(-x/y²)=-x/(x²+y²)所以
dz=[yIn(xy)+y]dx+[xIn(xy)+x]dy分开求导
z=arctanx/y+ln√(x^2+y^2)编微分的符号打不出来,只有用d代替了dz/dx=1/(1+(x/y)^2)*1/y+1/√(x^2+y^2)*1/2√(x^2+y^2)*2x=y/(x
2zdz+zdy+ydz=-sinydx-xcosydydz=[-sinydx-(xcosy+z)dy]/(2z+y)再问:不是先等式两边同时对x求偏微分再对y求偏微分吗?再答:偏微分和全微分的概念不
对x求偏导:2yz+2xyZ'x=2x+2zZ'x,得Z'x=(x-yz)/(xy-z)对y求偏导:2xz+2xyZ'y=2y+2zZ'y,得Z'y=(y-xz)/(xy-z)所以dz=Z'xdx+Z
对左右两边求导:(1+ez)dz=ydx+xdy.dz=1/(1+ez).(ydx+xdy).