Hi everyone,

I am having trouble determining how to obtain the area under the curve of a "complex" dsolve graph, as an example:

> restart;
> with(plots);
> g := diff(S(t), t) = t^2;
> q := diff(R(t), t) = t;
> ode1 := dsolve([g, S(0) = 1, q, R(0) = 1], [S(t), R(t)], numeric, events = [[t = 600, S(t) = 10^7], [t = 800, S(t) = 5*10^7]]);

> odeplot(ode1, [t, S(t)+R(t), color = blue, thickness = 2], 0 .. 1000, numpoints = 1000);...

I'm hoping that someone can help with this.  Below is an example of what I would like to do (part of a larger application):

> roll := rand(0 .. 1);

> roll();> s0 := %;                              

> roll();> s1 := %;                

With each execution, this will yield values for s0 and s1 that are randomly...

Hi group,

I am stumped and would appreciate some advice.  I'm trying to use the piecewise function in the context of dsolve,numeric.  As a simple example:

piwz := piecewise(S(t) < 40000, 0, S(t) >= 40000, 1);

eq1 := diff(S(t), t) = k1*S(t)-k2*S(t)*piwz

In this example, I want the value of piwz in eq1 to be a function of S(t).  However, when I use dsolve, numeric to solve this, and to plot using odeplot in the usual manner,...

Hi- I'm having trouble figuring out how to combine two separate DEplot graphs into one graph that represents the SUM of the two.  Not two separate DEPlot graphs in one figure, but the sum of two DEplot graphs in one figure.  I'm using Maple 14- anyone know how to do this?  It's probably simple, and I'm just missing it.  Thanks in advance.