设z=(x-y,xy)有连续的二阶偏导数,求аz/ax,az/ay
问题描述:
设z=(x-y,xy)有连续的二阶偏导数,求аz/ax,az/ay
答
u=x-y,v=xy
z'x=z'u*u'x+z'v*v'x
=z'u+z'v*y
z'y=z'u*u'y+z'v*v'y
=-z'u+z'v*x