Recently,I'm studying multivariable calculus. One of my friend said to me that the graph of $z=y^2-x^2$ has a saddle point .I don't understand the concept of saddle point with intuition.Can anyone explain the concept of saddle point with intuition and give reasons why the graph of $z=y^2-x^2$ has a saddle point?
Asked
Active
Viewed 928 times
3
-
http://math.stackexchange.com/questions/223776/finding-local-maxima-minima-and-saddle-points-of-fx-y?rq=1 – Mattice Verhoeven Jun 13 '15 at 06:22
1 Answers
4
On one direction, it looks convex, and on an another, it looks concave : you could comfortably sit on this saddle point.
(NB : it need not be really "concave" or "convex" in the rigorous sense).
Tlön Uqbar Orbis Tertius
- 3,194