Problem: Concave function of two variables
Problem
Show that \(f\left( x,y \right)=-x^2-y^2\) is strictly concave.
Solution
\[H=\left( \right)\]
\(\left| H \right|=4>0\) and \(f_{xx}^{''}=-2<0\) for all \(x\) : \(f\) is strictly concave.
Problem
Show that \(f\left( x,y \right)=-x^2-y^2\) is strictly concave.
Solution
\[H=\left( \right)\]
\(\left| H \right|=4>0\) and \(f_{xx}^{''}=-2<0\) for all \(x\) : \(f\) is strictly concave.