设函数u=f(xy,x/y),求:偏u/偏x,偏u/偏y?$(acontent)
问题描述：
设函数u=f(xy,x/y),求:偏u/偏x,偏u/偏y?
$(acontent)
答
∂u/∂x=[∂u/∂(xy)][d(xy)/dx]+[∂u/∂(x/y)][d(x/y)/dx]=yf₁'+(1/y)f₂'∂u/∂y=[∂u/∂(xy)][d(xy)/dy]+[∂u/∂(x/y)][d(x/y)/dy]=xf&...