Re: need help with Plot
- To: mathgroup at smc.vnet.net
- Subject: [mg88029] Re: need help with Plot
- From: dh <dh at metrohm.ch>
- Date: Tue, 22 Apr 2008 06:28:31 -0400 (EDT)
- References: <fuin33$9oh$1@smc.vnet.net>
Hi,
Plot can not deal with a varying number of functions. But as a work
around you may define new functions that are zero where you do not want
them to draw. As dirty trick, you may instead of returning zero, you may
return a symbol. In version 6, this has the effect, that this part is
not drawn.
Here an example with zero:
sol=4 t{Sin[2Pi t],1.2 Sin[ 2.2 Pi t],1.4Sin[ 2.4Pi t], Sin[2.6Pi t]};
{sol1[t_],sol2[t_],sol3[t_],sol4[t_]}=If[#<t,0,#]&/@sol
Plot[{sol1[t],sol2[t],sol3[t],sol4[t]},{t,0,5}]
Here an example with a symbol (NA):
sol=4 t{Sin[2Pi t],1.2 Sin[ 2.2 Pi t],1.4Sin[ 2.4Pi t], Sin[2.6Pi t]};
{sol1[t_],sol2[t_],sol3[t_],sol4[t_]}=If[#<t,NA,#]&/@sol
Plot[{sol1[t],sol2[t],sol3[t],sol4[t]},{t,0,5}]
hope this helps, Daniel
noravanq wrote:
> Hi,
>
> I have the following situation.
>
> f[z_,t_]=some function
> sol=Solve[f[z,t]==0,{z}]
> This returns
> {{z->sol1[t]},{z->sol2[t]},{z->sol3[t]},{z->sol4[t]}}
> I want to plot
> Plot[Select[{sol1[t],sol2[t],sol3[t],sol4[t]},#>t&]
> But it doesn't plot correctly. Depending on t, Select returns either 2 or 4 values. Plot correctly plots only the sections for which Select returns 2 values (it plots two curves), and doesn't plot anything for the interval for t, in which Select returns 4 values.
> Can anyone help to fix this?
>
> I should also mention, that if I restrict t to only the interval where Select returns 4 values, Plot correctly plots 4 curves.
>
> Thanks for your help.
>