Recent content by Israfil

Hey :) I got as far that I know I have to use the total impedance, which I calculated. Does anyone know, how I get the 2 resonant frequencies out of the total impedance? That'd be great! Isra

luckii, if that didn't help you, try with s = \frac{1}{2} a t^2 then you should be fine with both questions... good luck :)

hey berkeman, I really tried ... (with KVL) I started with \begin{eqnarray*} \begin{split} U_0 &=& R_1 I_a + L \dot{I}_a - L \dot{I}_b\\ 0 &=& \frac{1}{C} (I_b - I_c) - L \ddot{I}_b + L \ddot{I}_c\\ 0 &=& \frac{1}{C_3} I_c + \frac{1}{C}(I_c - I_d) - \frac{1}{C}(I_b-I_c)\\ 0 &=& L...

I multiplied them out because if I want to find something out about the angle between them, the scalar product tells you. So basically I rewrote your task to: Proof: (\vec A + \vec B)*(\vec A - \vec B) = 0 if |\vec A|=|\vec B| That's how I read your question...

hey berkeman, yes sorry, you're right... I was just waiting for someone to help me with the question I tried to figure out for hours without any luck, so I thought I could help answer some other questions meanwhile... Can you by any chance answer the question about oscillating circuits I...

sorry, there's been linebreaks missing, so here again: hey :) to your first question: ( \vec A + \vec B ) \cdot (\vec A - \vec B) = (a_1+b_1)*(a_1-b_1) + (a_2+b_2)*(a_2-b_2) + (a_3+b_3)*(a_3-b_3)\\ = a_1^2-b_1^2 + a_2^2 - b_2^2 + a_3^2 - b_3^2\\ = a_1^2+a_2^2+a_3^2 -...

hey :) to your first question: ( \vec A + \vec B ) \cdot (\vec A - \vec B) = (a_1+b_1)*(a_1-b_1) + (a_2+b_2)*(a_2-b_2) + (a_3+b_3)*(a_3-b_3)\\ = a_1^2-b_1^2 + a_2^2 - b_2^2 + a_3^2 - b_3^2\\ = a_1^2+a_2^2+a_3^2 - (b_1^2+b_2^2+b_3^2) if perpendicular, this is supposed to be 0, so...

third question: the forces must be arranged in a way that the sum of them is the zero vector.

by the way: What's KVL and KCL?

thank you so far :) I know its a filter ... it's more a matter of language because I'm German and not that much used to writing about such topics in English. I hope you can help me anyway. I'm familliar with TeX, I just didn't know how to use it in here...

Hi :) I've e.g. tried 1: 2*U_c + U_C3 = 0 2: U_c + U_L = 0 => 1: 2/C \int I_C dt + 1/C_3 \int I_L - I_C dt = 0 2: 1/C \int I_C dt + L * d/dt I_L = 0 => 1: 2/C* I_C + 1/C_3 * (I_L - I_C) = 0 2: L* d^2/dt^2 I_L + 1/C * I_C = 0 the problem I have here is - in my opinion that I...

The forces applying on the wagon are F=140 N (uphill), F_h (downhill), F_g (Gravity) and F_n (at right angle onto the uphill ground). Now you need to draw them and figure out F_h because F - F_h is the force that pulls up the wagon. You'll discover from your drawing the F_h = F_g*sin(18.5°) with...

solution Hey :) Both players are accelerating, so the equation for both their movement is first player s_1 = 1/2*a_1*t^2 2nd player s_2 = 1/2*a_2*t^2 with a_1 = 0.5 m/s^2 and a_2 = 0.3 m/s^2 you know that s_1 + s_2 = 48m Now you sum up both players' equations and receive: s_1 + s_2...

Dear readers :) I've tried to figure this out for quite some time now, I hope anyone can help me on this: I'm looking for the differential equations for 2 PARALLEL oscillating circuits coupled by a capacitor. I've tried to start similar as in http://www.ruhr.de/home/leser/mathe/355.pdf...