Recent content by jimbobian

Thanks for pointing that out, at least now I know what it is called and that it seems to be a general result (for some envelope). But is it possible to show that, in this case, the envelope is a straight line with gradient m_c as above. I find the following two restrictions: a=c\cosh(b/c) c/b...

Hi all, this question stems from a homework question but is not the homework question itself, more a discussion on something I found, hence why I have put it here. The question involved using variational calculus to minimise the surface area of a soap bubble to find the shape it would take. The...

I did the question with that equation for R and got the given answer, can you show exactly what calculations you are doing at each step please - the value you have given for the momentum is incorrect (far too small)

The question asks for the speed of the electron after going 1m which you have calculated but then asks for the magnetic field needed after the electron exits the LINAC which is 3.2km. You have used the velocity for the first part which won't be correct.

Thank you! Yes, the actual integration, as uart pointed out, isn't challenging I just got hung up on why this didn't work. Thank you both, my issue is solved!

Damn, one month after school finishing and I'd already forgotten to be on a look out for that, despite the number of times my teacher brought it up! That form would certainly make evaluating it easier (and thank you for spotting it), but I would also like to know why my method didn't work?

Homework Statement Evaluate \int{\frac{1}{nln(n)} dn } Homework Equations The Attempt at a Solution I know the answer thanks to WolframAlpha, I just want to understand why my method didn't work. I took a stab at parts using: u=\frac{1}{ln(n)} \frac{dv}{dn}=\frac{1}{n} So...

Ignore this now, figured it out!

Homework Statement Not technically a homework problem, has arisen as a point on my A-Level specification and I'm a little unsure as to how they are seeing this situation. "Relate qualitatively the instantaneous e.m.f. induced in a coil rotating at right angles to a magnetic field to the...

Thanks for your response. 1) ln(t), so this would suggest it doesn't converge for n=1? 2) Firstly I'm not sure where you've got this fraction from, I can't find it in any working of yours or mine? It would converge for n>1 for sure. For n=1 it won't converge, but for n<1 I have no idea?

Homework Statement If In denotes \int_0^∞ \! \frac{1}{(1+x^2)^n} \, \mathrm{d} x Prove that 2nI_{n+1} = (2n-1)I_n, and state the values of n for which this reduction formula is valid. Homework Equations The Attempt at a Solution I_n=\int_0^∞ \! \frac{1}{(1+x^2)^n} \, \mathrm{d} x =\int_0^∞...

Ok I've figured out why the minus sign shouldn't have been there, I forgot that what you actually do to find the CDF is: \int_{-∞}^{x} p(t)dt Which sorts out the minus sign, other problem still remains? EDIT: I'm talking rubbish this hasn't fixed a thing! EDIT2: Turns out it fixed both...

Ok, this one's got me stumped! Let's take as an example the probability density function for a random variable X so that: f(x) = \frac{4}{3x^{3}} 1≤x<2 f(x) = \frac{x}{12} 2≤x≤4 f(x) = 0 So the CDF for this variable comes out as: F(x) = \frac{-2}{3x^{2}} 1≤x<2 F(x) =...

Yes! No problem

https://www.physicsforums.com/showthread.php?t=94379