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Re: Simple equation won't plot

  • To: mathgroup at smc.vnet.net
  • Subject: [mg82950] Re: [mg82917] Simple equation won't plot
  • From: DrMajorBob <drmajorbob at bigfoot.com>
  • Date: Sun, 4 Nov 2007 06:13:13 -0500 (EST)
  • References: <17144801.1194080632831.JavaMail.root@m35>
  • Reply-to: drmajorbob at bigfoot.com

You misspelled Plot (with the numeral 1 in place of the letter l).  
(Whoever decided the two should look so nearly identical is roasting in =

hades, I hope.)

m = 70; a = 0.08; x0 = 5000; g = 9.81;
x[t_] = x0 - m*Log[Cosh[t*Sqrt[g*a]/Sqrt[m]]]/a
Plot[x[t], {t, 0, 60}]

works just fine.

The second line (a) isn't an equation and (b) uses t_ on the left to  
define a pattern named t.

Bobby

On Sat, 03 Nov 2007 03:27:03 -0500, Bert Aerts (rm x)  
<bert.aertsx at advalvasx.be> wrote:

> When I type following commands in Mathematica 6.0.1:
> m = 70; a = 0.08; x0 = 5000; g = 9.81;
> x[t_] = x0 - m*Log[Cosh[t*Sqrt[g*a]/Sqrt[m]]]/a;
> P1ot[x[t], {t, 0, 60}]
> I don't get a plot, but instead:
> P1ot[5000 - 875. Log[Cosh[0.105884 t]], {t, 0, 60}]
> How can I get a real plot? I tried [N[x[t]] and Evaluate[x[t]] but  
> nothing
> worked...
> Why is t_ used in the second equation?
> The source of these equations is Ferdinand F. Cap's book "Mathematical
> methods in physics and engineering with Mathematica"
>
>
>



-- 

DrMajorBob at bigfoot.com


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