对于这样的抽象函数按照步骤一步步求导即可z=f(x+y,x-y)那么求偏导得到z'x=f1' *(x+y)' +f2' *(x-y)'=f1' +f2'z'y=f1' *(x+y)' +f2' *(x-y)'=f1' -f2'
