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Re: Simple equation won't plot

  • To: mathgroup at smc.vnet.net
  • Subject: [mg82952] Re: [mg82917] Simple equation won't plot
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Sun, 4 Nov 2007 06:14:15 -0500 (EST)
  • Reply-to: hanlonr at cox.net

When I paste your statement into a notebook, the word Plot isn't recognized as a reserved word. Doubleclicking it and retyping Plot fixed this and everything worked as expected. Perhaps there is a hidden character in the expression.

The t_ is a pattern with the name t and specifies that the argument can be anything not just t. Look up Blank.


Bob Hanlon

---- "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"
> 
> 



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