一道大一高数题1.函数f(x,y,z)=-2x^2在x^2-y^2-2z^2=2条件下的极大值是2.若函数z=f(x,y)=x^2+2xy+3y^2+ax+by+6在点(1,-1)处取得极值,则常数a=?b=?

问题描述:

一道大一高数题
1.函数f(x,y,z)=-2x^2在x^2-y^2-2z^2=2条件下的极大值是
2.若函数z=f(x,y)=x^2+2xy+3y^2+ax+by+6在点(1,-1)处取得极值,则常数a=?b=?

1.x^2-y^2-2z^2=2
x^2=2+y^2+2z^2>=2
所以f(x,y,z)=-2x^2