# Corner of extremals (Erdman)

1. Jan 29, 2016

### baby_1

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

and tried to find relationship between P and q that aren't the same to have a corner.

But as you see it doesn't give me a good value for lambda and I can't derive lambda>2 . Is it correct approach? or should I test and other way?

Thanks

2. Jan 29, 2016

### Ray Vickson

Your posting is incomprehensible to other readers: we have no idea at all what you mean by $p$ and $q$, since they were not mentioned anywhere in your problem.

Also: I am sure that your statement $\text{Erdman's Equation} = \partial F / \partial y'$ is meaningless: an equation is not a quantity.