Plot Graphene Distribition Problem

[vesta33]

Hi.

According to the attached article I couldn't draw fig1 with eq1 using mathematica.

 

[NascentOxygen]

Hi vesta33. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif

Is there a question or something you intended should accompany your post?

Not that I will be able to help, but someone else may offer to ...

 

[DrClaude]

Is there a question or something you intended should accompany your post?

Not that I will be able to help, but someone else may offer to ...

I'll bite.

You realize that $g(\bar\omega^2)$ is defined by different equations depending on the value of $\bar\omega^2$? And that the figure in the paper plots $g(\bar\omega^2)$ as a function of $\bar\omega^2$, not $\bar\omega$?

 

[vesta33]

NascentOxygen and DrClaude, thank you for answers. I plotted this without elliptic integral. But this article referred to elliptic integrals. DrClaude, I am aware of your writings but mathematica has given error mesage:

 

[DrClaude]

Instead of using w^2 in the equation for g7, define a variable w2 that corresponds to $\bar\omega^2$.

 

[vesta33]

I had tried.

 

[DrClaude]

In the argument of the elliptic integral, you're missing the cube in $(2-3\bar\omega^2)^3$.

 

[vesta33]

You are right. But after I tried all variable ranges with correct code, nothing changed. Mathematica file is attached for anyone intersted in this plot. Thanks for help.

 

[DrClaude]

You posted this in a homework forum, but am I correct in assuming that this is not homework?

Looking at your file, you have in it

g2 = (9/\[Pi]^2) ((1 - 2 w)/(3 w (2 - 3 w)^3)^(1/2)) 
       (EllipticK[(1 - 2 w)/(w (2 - 3 w)^3)])^(1/2);
Plot[g2, {w^2, 0, 1}]

First, the argument of the elliptic integral is incorrect. The square root should be over the argument itself, not the entire integral. Second, you need to plot with respect to w, not w^2. Third, the equation for g you have there is only valid in the range $1/3 \leq \bar\omega^2 \leq 1/2$. Therefore, you should have

g2 = (9/\[Pi]^2) ((1 - 2 w)/(3 w (2 - 3 w)^3)^(1/2))
      EllipticK[((1 - 2 w)/(w (2 - 3 w)^3))^(1/2)];
Plot[g2, {w, 1/3, 1/2}]

 

[vesta33]

I should stress that I know mathematica. I had tried all possibly variaions before wrote here. If anyone wants help me please first of all run the code. I think mathematica or the article has a bug. Please nobody reply the message without running the code.

 

[DrClaude]

I will try to be as diplomatic as possible, but your latest post has made me cross. I was guiding you towards the solution to your problem, but instead of trying what I suggested, you reply without any new attempts.

I should stress that I know mathematica.

Then you should know why the statement

Plot[g2, {w^2, 0, 1}]

is not valid.

I had tried all possibly variaions before wrote here.

Obviously not, because you have not been able to reproduce the graph.

If anyone wants help me please first of all run the code.

I did, told you what was wrong, and even gave you a correct replacement code, which is at least valid for part of the $\bar{\omega}$ domain.

I think mathematica or the article has a bug.

Both are fine. I was able to reproduce the figure in a couple of minutes. Before you ask for my code, note that this is not how things are done on PF. We don't feed you fish, we help with the fishing.

Please nobody reply the message without running the code.

Please do not reply before taking into account the replies of others.