设z=xf(y⼀x,y)求二阶偏导

2025-03-04 07:41:25
推荐回答(1个)
回答1:

Zx=[(x+y)-x]/(x+y)^2=y/(x+y)^2
Zy=-x/(x+y)^2
Zxx=-2y/(x+y)^3
Zyy=2x/(x+y)^3
Zxy=(x-y)/(x+y)^3