- #1
krakatoa
- 7
- 1
Homework Statement
f[/B] is an armonic function and C2(R2)
a) Suposse a point P0 / fxx(P0) > 0. Prove that P0 is not a extreme value.
b) consider D = {(x,y) / x2 + y2 < 1} and suposse fxx > 0 for all (x,y) in D. Prove that: if f(x,y) = 0 in x2 + y2 = 1, so f(x,y) = 0 for all (x,y) in D.
Homework Equations
In armonic funcions laplacian = 0
The Attempt at a Solution
[/B]
I intuit that P0 is a saddle point, and I try to show this in the hessian matrix and I can´t