问几个数学题1设F(X,Y)=(E^x)(arctan(x+y) ,简单的描述是1设F(X,Y)=(E^x)(arctan(x+y))则，F'（0,1）=2设Z=（e^x）（sin(x+y)）则dz|（0，π）=  A-dx+dy B +dx+dy -dx-dy D+dx+dy,答案是1设F(X,Y)=(e^x)(arctan(x+y))则，F'（0,1）= 
解：F'x=e^x{arctan(x+y)+1/[1+(x+y)^2]},
F'y=e^x/[1+(x+y)^2],
∴F'x(0,1)=arctan1+1/2=π/4+1/2.
F'y(0,1)=1/2.

2设Z=（e^x）（sin(x+y)）则dz|（0，π）= 
解：dz=e^x[1+cos(x+y)]dx+e^x*cos(x+y)dy,
∴dz|(0,π)=(1+cosπ)dx+cosπdy=-dy.