z=f(xy,y)的偏导数d^z/dxdy

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z=f(xy,y)的偏导数d^z/dxdy
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z=f(xy,y)的偏导数d^z/dxdy
z=f(xy,y)的偏导数d^z/dxdy

z=f(xy,y)的偏导数d^z/dxdy
由题知,
z=f(xy,y)
所以,
dz/dx=f1(xy,y)*y

d²z/dxdy
=d(dz/dx)/dy
=d(f1(xy,y)*y)/dy
=f1(xy,y)+y[f11(xy,y)*x+f12(xy,y)]
=f1+xy*f11+y*f12
其中,f(u,v)对u求导记做f1,对y求导记做f2

dz/dy=f1'*x+f2'
d^2z/dxdy=d(f1'*x+f2')/dx=f1'+xyf11''+yf21''

好容易,我就是不晓得怎么书写出来,我先吃个饭。。。