问题 填空题

,则f’x(x,y)-f’y(x,y)=______.

答案

参考答案:(x-y)exy(2-x2-y2)

解析:令x+y=u,x-y=v,则f(u,v)=(a2+v2)euv
f(x,y)=(x2+y2)exy
f’x(x,y)-f’y(x,y)=2xexy+y(x2+y2)exy一2yexy-x(x2+y2)exy
=(x-y)exy(2-x2-y2)

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