# [Tutor] coding help with maxwell-boltzmann distribution

William Ray Wing wrw at mac.com
Thu Oct 12 23:48:10 EDT 2017

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> On Oct 12, 2017, at 4:22 PM, Cameron McKay <cmmckay at ualberta.ca> wrote:
>
> Hello,
>
> I've never used python trying to plot a graph. Thus I am having
> difficulties trying to plot the maxwell-boltzmann distribution. right now
> i've defined the y-axis given the probability, but the difficult part is
> trying to plot x in the form of:
>
> x = v/(2kT/m)^(1/2)

First of all, this only part of the formula for the Maxwell Boltzmann distribution function.  It is usually written as:

F(v) = (m/2 pi kT)^3/2 * 4 pi v^2 exp(-mv^2/2kT)

The independent variable is v, everything else is constants.  So what you want is an array of values of v (which will be the x axis).  Then use a for loop to calculate F(v) for each v in the range. Finally, importing matplotlib, and plotting F(v), the y axis, as a function of the x axis will give you your (sort of) bell curve.
Hope these hints help.
Bill

>
> before i used the linspace function but i believe that was wrong as it just
> gave me an exponential growth function as i need a bellcurve.
>
> Thanks for looking into this,
>
> Cameron
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