Recent content by Jonas Rist

No prob, I got the idea of your solution, so I noticed that on my own. Jonas

Ok, thanks! I see now that my first way to solve the problem was wrong. Ciao Jonas

Hi, thanks for the answer. The normal component of the dipole field is E_r=\frac{qd 2 cos(\theta)}{4\pi\epsilon_0 r^3} So I thought of choosing \sigma(\theta)=-\frac{qd 2 cos(\theta)}{4\pi R^3} then the normal component should be canceled out according to the following law...

Hi, I have problems solving this: Given: A sphere(Radius R) with a mathematical dipole in its center. I have to find the charge distribution on the sphere´s surface, \sigma(r,\phi,\theta) so that the resulting potential is zero for r>R. I think that...

Hello again, another problem: given: a function f:[0,\infty)\rightarrow\mathbb{R},f\in C^2(\mathbb{R}^+,\mathbb{R})\\ The Derivatives f,f''\\ are bounded. It is to proof that \rvert f'(x)\rvert\le\frac{2}{h}\rvert\rvert f\rvert\rvert_{\infty}+\frac{2}{h}\rvert\lvert...

Ah, sorry, actually one has to show that the function is differentiable from the left and from the right(but these derivatives don´t have to be equal, as your example shows clearly). Jonas

Hello, how can I proof this: given: a convex function on an open interval I,which is a subset of R. I have to show that the function can be differentiated on the whole interval. I already proved the following for a<b<c, a,b,c in I: f(b)-f(a))/(b-a)<(f(c)-f(a))/(c-a)<(f(c)-f(b))/(c-b)...