全微分精通者帮忙! 设z=z(x,y)由方程e的z次方-xy的2次方+sin(y+z)=0确定,求dz

2025-05-15 15:41:13
推荐回答(2个)
回答1:

方程e的z次方-xy的2次方+sin(y+z)=0
e^z-xy^2+sin(y+z)=0
设F=e^z-xy^2+sin(y+z)
F分别对x、y、z求导
Fx^'=-y^2
Fy^'=-2xy+cos(y+z)
Fz^'=e^z+cos(y+z)
Z对x的偏导数为  -Fx^'/Fz^'=y^2/[e^z+cos(y+z)]
Z对y的偏导数为  -Fy^'/Fz^'=-[-2xy+cos(y+z)]/[e^z+cos(y+z)]=[2xy-cos(y+z)]/[e^z+cos(y+z)]
dz=-Fx^'/Fz^'dx+-Fy^'/Fz^'dy
=y^2/[e^z+cos(y+z)]dx+[2xy-cos(y+z)]/[e^z+cos(y+z)]dy

回答2:

(y^2+2xy-cos(y+z))/(e^z+cos(y+z))