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