设z=f(x/y),且f可微,求dz
问题描述:
设z=f(x/y),且f可微,求dz
答
dz=δf/δxdx+δf/δydy
=f`(x/y)/y*dx+f`(x/y)*(-x/y²)dy
=f`(x,y)(dx/y-xdy/y²)