Re: changing variable in an equation

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

```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);

Plot[
Evaluate[
Table[
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 comcast.net> 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.
Thanks

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.

thanks
Jake

```

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