Recent content by Old Guy

I absolutely found Dirac to have the best explanation of Dirac notation (Go figure!)

Let me just add: IT'S NEVER TOO LATE TO PURSUE YOUR PASSION I got a chemical engineering degree in 1978, and had a very satisfying career. In 2006, I decided I wanted to understand quantum mechanics, so I went back to school. I got a Schaum's outline for calculus (because I hadn't done calculus...

Homework Statement I know that intensity is power per unit area. When I do a dimensional analysis, it reduces down to mass per cubic time. Is there any physical significance to that? Homework Equations I=P/A The Attempt at a Solution

If your problem is that you have vectors x and y that contain your data, and you want to find A, B, C and D for the equation shown as a fit to that data, try the curve fitting toolbox. Run cftool, select x and y as your data set, then under fit select custom equation and you can enter the...

Thanks for your help, but I could not get this to work because I am trying to change a .fig file in the property editor. I tried generating the code, and then making the modification there, but I was unable to save as .fig after that. Any suggestions?

I want to put the following as an axis label on a plot, but I cannot figure out how to get the bar on top in Matlab \bar \xi Thanks.

Of course, now I get it! Thank you.

Thank you, but can you expand on your answer a bit? Not sure I understand what you mean in your second sentence.

Homework Statement I'm working with a 0ne-dimensional random walk and looking at Fick's second law, below. All I've read seems to take D = 1/2 as a given for ordinary diffusion, but where does this come from? Is there a way to derive it? Homework Equations \frac{\partial } {{\partial...

Thanks to you both. Ultimately it was a path issue, although I thought I had checked that thoroughly before I posted.

I downloaded largestcomponent.m today and it runs fine on my PC (Win 7 Enterprise SP 1) but when I try it on my Linux machine (Ubuntu 10.04 LTS) I get this message: ? Undefined function or method 'largestcomponent' for input arguments of type 'double'. Even if I put the function file in...

I am trying to make a plot of four pairs of time series. The plot appears fine; I have two lines in each color as I want. The problem, in this case, is that the first two legend items both have red lines, and the second two both have black lines. I want each legend entry to match the color of...

Thank you for your help, diazona. I still haven't completely wrapped my mind around probability densities yet. Nonetheless, with your suggestion (and some mathematical sleight of hand) I was able to satisfy myself that p(x,t) in the form of 2/x made the terms vanish as needed. A function that...

I understand, of course, about the boundary terms. It seems to work out if I assume that p(0,t)=1 (ie, the particle(s) all start at the origin) and that p(\infty,t)=0 (there is nothing at the infinite boundary). This still leaves me multiplying zero times infinity, and isn't that considered to...

Homework Statement For ordinary 1D diffusion show that the mean value of the square of the position is equal to 2Dt Homework Equations \left\langle {x^2 \left( t \right)} \right\rangle \equiv \int\limits_0^\infty {x^2 p\left( {x,t} \right)dx} \frac{\partial }{{\partial t}}p\left(...