ISI 2017 PEA Q.29

Posted by Nak on Mar 25, 2018; 5:25am
URL: http://discussion-forum.276.s1.nabble.com/ISI-2017-PEA-Q-29-tp7608914.html

 Let f : R2 → R be a twice-differentiable function with non-zero second partial derivatives. Suppose that for every x ∈ R, there is a unique value of y, say y∗(x), that solves the problem
max y∈R f(x, y).
Then y * is increasing in x if