Re: changing variable in an equation

*To*: mathgroup at smc.vnet.net*Subject*: [mg116378] Re: changing variable in an equation*From*: DrMajorBob <btreat1 at austin.rr.com>*Date*: Sat, 12 Feb 2011 05:20:22 -0500 (EST)*References*: <201102110917.EAA07980@smc.vnet.net>*Reply-to*: drmajorbob at yahoo.com

You have a missing parenthesis, so I'll have to guess where you wanted it. Your three examples don't seem to match the phrase "working from -100 to 100". And there's a third variable -- x -- that you haven't explained. I'll give it a fixed value. So... working from -10 to t+10 to save time, and t varying from 0 to .1 so that everything isn't obscured by the scale: Clear[v] v[i_, x_, t_] = -67 + (10 (i - 1) + 67) x E^(-19 x t)/10; x = 3; Plot[Evaluate@Table[v[i, x, t], {i, -10, 10}], {t, 0, .1}, PlotRange -> All] In case it's x that should vary from -100 to 100, then I don't know what values i should take on. But... if you want to vary both, here's an example: Plot[Evaluate@Table[v[i, x, t], {i, -10, 10}, {x, 0, 3}], {t, 0, .1}, PlotRange -> All] Notice that this is colored differently: Plot[Table[v[i, x, t], {i, -10, 10}, {x, 0, 3}], {t, 0, .1}, PlotRange -> All] That's what Evaluate is about, in the other plots. Bobby On Fri, 11 Feb 2011 03:17:10 -0600, 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 -- DrMajorBob at yahoo.com

**Follow-Ups**:**Re: changing variable in an equation***From:*"J and B" <noslowski@comcast.net>

**References**:**changing variable in an equation***From:*"J and B" <noslowski@comcast.net>