Z'x=e^(xy) · y + 2x arctanx +(x²+y²) · 1/(1+x²)=ye^(xy) +2xarctanx +(x²+y²)/(1+x²)Z'y=e^(xy) · x +2y arctanx =xe^(xy) +2yarctanx
Z=e^(xy)+(x^2+y^2)arctanx,∂z/∂x=ye^(xy)+2xarctanx+(x^2+y^2)/(1+x^2),∂z/∂y=xe^(xy)+2yarctanx.