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These are questions asked by reemeaaaah


I am trying to find the maximum of values in dsolve. In part 1 we solve the equation. In part 2 we do a doolop to know the values for specific time such as t=2. In part 3 we try to give this values names such as y[i] then to find the maximum of these values but it did not work for the maximum it gave y6 instead of the value.


Also, is it possible to save all values from dsolve  to a file the call it to find the maximum at each t?


I am trying to get a shaded area in my plot but I could not.

First we solve ODE without randomness:

ode := diff(U(t), t) = -(A+B*U(t))*U(t);

Then we add randomness to ODE and solve:

ode2 := diff(U(t), t) = -(A+r(t)+B*U(t))*U(t);

A with randomness for r in R=( - 0.0001/365, 0.0001/365) is:

A(t,r)= A+r

Where A is constant =  0.0001/365

We plot both solution. For the plot I...


I am trying to plot the solution for eq1 and eq2 for different values of mu.  When I plot  this:

 f := proc (x) options operator, arrow; mu*abs(F[N]-g)*signum(x(t)) end proc;

it works.

When I do the same for the solution it won’t work.

Please any help or advise.


This is the code:

> restart;

> with(plots);

> with(DEtools);

> k := 100; L := .25; M := .5; g := 4; mu := 0.2e-1;


I am trying to add a random variable in ODE and solve it.

I chose A as the random variable.

Randomness in A will define like:

A with randomness for s in S=(-0.05,0.75) is:

A(t,s)= A`(t)+s

Where A`(t)= 0.25+ 0.0037t , if 0<= (t,365)<=182

                    0.5+ 0.0045 t  , if 182<= (t,365)<=365


I am trying to add an if statement to maple code for example if U(tk) less or equal to 4 then 
the initial condition=0 else the initial condition=value .
I am getting this error:
Error, cannot determine if this expression is true or false: U(365)


 k := 0; B[1] := 0.001/365; B[2] :=0.002/365:

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