z=e^(xy) sin(x＋y)∂z/∂x=ye^(xy) sin(x＋y) ＋e^(xy) cos(x＋y)=e^(xy) [ysin(x＋y)＋cos(x＋y)]∂z/∂y=xe^(xy) sin(x＋y) ＋e^(xy) cos(x＋y)=e^(xy) [xsin(x＋y)＋cos(x＋y)]
