Question

7.设a=x+y+z+2其中z=f(x,y)为由方程x+y+z=

Answer 1

问：7.设a=x+y+z+2其中z=f(x,y)为由方程x+y+z=

答：你好，7.设a=x+y+z+2其中z=f(x,y)为由方程x+y+z=解答：F(x^2+y^2+z^2)-x-y.dz/dx=2xF'+2z*(dz/dx)F'-1,dz/dy=2yF'+2z*(dz/=dy)F'-1,-> (y-z)*dz/dx+(z-x)*dz/dy=(y-x)(2zF'-1)+2zF'[(y-z)*dz/dx+(z-x)*dz/dy]-> (y-z)*dz/dx+(z-x)*dz/dy=x-y (2zF'-1!=0).