Excuse me sir, for the late reply. I think I didn't understood it first, then forgot about it, now I stumbled across it and still haven't figured it out
ρ . A . d = σ . A
ρ . dx = σ
Is this what you were implying?I don't see how R sin θ dθ equals the thickness of my disk, since R sin θ points...
Hi all,
According to wikipedia:
Can someone explain to me with a mathematical proof the following:
$$ \frac {\partial f(x)} {\partial v} = \hat v \cdot \nabla f(x) $$
I don't get this identity except the special example where the partial derivative of f(x) wrt x is a special kind of a...
I think the solution is just wrong because the last step isn't correct?
Edit:
Looks like the solutions manual from Zangwhil contains errors.
This is from a site I found on the internet (check problem 4d)
https://pa.as.uky.edu/sites/default/files/Phy416G-HWSol4.pdfbut now
dσ = 2πρR sin θdθ...
Find E(r) inside and outside a uniformly charged spherical volume by superposing the electric fields
produced by a collection of uniformly charged disks.
a+b) Given equations, sketch of problem
This is the equation in the handbook for a disk (but in the exercises the z becomes x, without loss of...
Hi,
Here is the complete exercise and solution from Zangwhil Modern Electrodynamics. Since my question is about the levi-civita symbol, I thought it would be better to post it here since it is a tensor.
So in the step e(ijk) D(jk) = e(ijk)D(jk) + e(kj)D(kj)
So The e(kj)D(kj) part is wrong and...
Hi all,
Can someone explain me the last two steps?
I don't know why suddenly there is a term with only two indices, and then in the last step you do something distributive and again three indices.
Thanks in advance
Ok, so partial integration. integral (fdg) = fg - integral (gdf)
f = z-Ru
dg = du / (R² +z² -2zRu) ^ 3/2
For g I get
1 / ( (Rz) * (R² + z² -2*R*z*u)^1/2)
fg = (z-Ru) / ( (Rz) * (R² + z² -2*R*z*u)^1/2)
now the integral part - integral ( g d f)
df = -R du
So
The integral to solve
Rdu /...
I get something extremely messy. Here is the first part, the second part with integration by parts,I'll do it again tomorrow.
So the first term
integral (z du / (R² + z² - 2 Rz u) ^3/2 )
d(R² + z² - 2 Rz u) = -2 R z du
The integral becomes
-1/2R * integral ( d(R² + z² - 2 Rz u) / (R² + z²...
Hi all,
"Integral can be done by partial fractions - or look it up" So second line, that's what I want to do.
How to deal with this? What substitution can I use? Never encountered partial fractions with non-integer exponents.
Someone give me a tip?
Thanks in advance
Hi myself,
I found out I need to include something like 1- ( stuff going in the z direction after k scattering) / (stuff that would go in z direction if there was no scattering at all), so 1 - k' projected on z axis /k = 1 - (k cos theta) / k
Yes, I'm a noob.
So I'll start over. :')
Hi,
Sorry for the late reply.
Hope this is somewhat more clear, because last post was a bit messy. Still haven't learned LaTex.
Is this valid?
I couldn't evaluatie the last integral, because of the square.
Do I need to use partial fractions?
Thanks
This is what I got uptil now, but I have to leave.
Thanks for help, give me feedback if you want to, and I will post update when I'm back, probably tomorrow. Thanks for the patience anyway!
How come dk' is a volume element, it's the derivative of a vector. Most textbooks, the volume element is called a d tau or a dV
My head is a mess. It's like I completely forgot how to calculus.
Good news: I know I'm wrong.
Really don't see it
Mr
6 hours and I still have no clue, can you please hold my hand and solve it with me. I mean, just say what I have to do, I will solve it, but give me instructions.
I mean what's the deal with the dirac function and the dk', it's supposed to be a volume element and the dirac term, why isn't...