dz=arctan(x+y)/(x-y) dx+arctan(x+y)/(x-y) dy =((x-y)/(1+(x+y)^2)+(x-1)arctan(x+y))dx/(x-y)^2+((x-y)/(1+(x+y)^2)-(1-y)arctan(x+y))dy/(x+y)^2
希望能解决您的问题.
z=arctan（x-y）,求dz
dz=arctan(x+y)/(x-y) dx+arctan(x+y)/(x-y) dy =((x-y)/(1+(x+y)^2)+(x-1)arctan(x+y))dx/(x-y)^2+((x-y)/(1+(x+y)^2)-(1-y)arctan(x+y))dy/(x+y)^2
希望能解决您的问题.