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Re: changing variable in an equation

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  • Subject: [mg116369] Re: changing variable in an equation
  • From: Bob Hanlon <hanlonr at>
  • Date: Sat, 12 Feb 2011 05:18:45 -0500 (EST)
  • Reply-to: hanlonr at

I am guessing that each x in your equation is intended to represent multiplication. You are also missing a parenthesis which I put at the end but may have to be moved.

v[a_, t_] = -67 + (a - (-67)  E^(-19  t)/10);

   Tooltip[v[a, t], a],
   {a, -100, 100, 10}]],
 {t, 0, 5},
 Frame -> True,
 Axes -> False]

Plot3D[v[a, t], {t, 0, 5}, {a, -100, 100}]

Bob Hanlon

---- J and B <noslowski at> wrote: 

Below is an equation that I am working on. I know there is some way to work
it out better than what I am doing.  I would like the variable a to change
in increments of 10, from -100 to 100.  
my main equation is:  v = -67+(a-(-67) x E ^ (-19 x t)/10
what I am doing:
v1= -67+(0-(-67) x E ^ (-19 x t)/10; 
v2= -67+(-10-(-67) x E ^ (-19 x t)/10;
v3= -67+(-20-(-67) x E ^ (-19 x t)/10;
and so on and working from -100 to 100
Then I use
Plot [ { v1,v2, v3 ........},{t,0,5}, PlotRange -> All]
Please note that I have added some spaces in to make it more readable.

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