Z=f'x(x,y)=xy*[x^(xy-1)]*y
Z=f'y(x,y)=xy*[x^(xy-1)]*x答案是Z=f'x(x,y)=yx^xy(lnx+1),Z=f'y(x,y)=x^(xy+1)lnx,求解答过程请问是Z=(x^x)y还是Z=x^(xy)Z=x^(xy)Z=x^(xy)两边取对数:lnZ=xylnx两边同时对x取导有Zx/Z=ylnx+xy/x=ylnx+y有:Zx=x^(xy)[ylnx+y]=yx^xy(lnx+1),两边同时对y取导有:Zy/Z=xlnx则有:Zy=xlnx[x^(xy)]=x^(xy+1)lnxZx=x^(xy)[ylnx+y],为什么要乘起来?