Recent content by loesung

I'm new to electronics, and using my new equiptment I would like to generate a sine signal on my function generator and display it on my oscilloscope. Equipment: * The scope is Rigol DS1054Z * Function generator is a $60 digital chinese. My problem is: When I plug connect the function...

If a pendulum consisting of a string and a bob is allowed to swing in a vacuum vs in air, which has larger period?

Homework Statement Given two inductors, connected in parallel connected to a battery, why do the following emf relations hold? $$\mathcal{E}_1 = - N_2 A \frac{d B}{d t} = -M\frac{d I_1}{d t } \\ \mathcal{E}_2 = -L_2 \frac{dI_2}{dt}- M \frac{dI_1}{dt}$$ See attachment ! Homework Equations...

I was given the following explanation, though I really don't understand what's going on with eqs. (3) and (4): Using Taylors theorem, write u(x)=u(x_0)+\nabla u(x_0)\cdot(x-x_0)+\frac{1}{2}(x-x_0)^T\nabla^2 u(x^*)(x-x_0) Because we suppose a max is obtained, we have from vector...

Hello! I would like to show the following: u\in C^2(U) \cap C(\bar{U}) satisfies \Delta u(x)>0 for any x\in U, then \max_U u cannot be achieved by any point in U. Here, u\in \mathbb{R}^n, i.e. it's not complex valued. Apparently, one can use the Taylor expansion formula to show this...

And there's 29/2+7=21.5. Just say your almost 21 :-)

For beginning pde Hans Weinberger´s book Int. to PDE, is quite good, because it introduces the usual heat-wave eqns. at a beginner´s level. The text is elementary without being needlessly verbose, and makes use of complex numbers as well as some complex analysis. The mathematical sophistication...