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I am trying to solve the following system using the function "solve", but the message "warning solutions may have been lost" appears.


This is my script (a,b,c,d,e,f, Resp, Malcyt,Pyrcyt are parameters). The unknown variables are Citcyt, Citmt,Malmt,Pyrmt:

e1 := 0 = a.Pyrcyt-a.Pyrmt+(b-c).Malmt;
e2 := 0 = d.Malcyt+e.Citmt-(d+b+c).Malmt;
e3 := 0 = f.Citcyt+c.Malmt-(e+f).Citmt;
 e4 := 0 = 2.*e.Citmt+(b+c).Malmt-Resp;

Hi all,

I read the help on using parameters, then I tried to modify the example

f := proc(a, b, c)

    if _params['b','c'] = NULL then
    elif _params['c'] = NULL then
    a + b
    a + b + c

    end if

end proc:

I can't really spot where it went wrong, but it just wouldnt execute as I would expect...


Hey guys..

I need some help on determining the correlation coefficient between my data points for an Influenza epidemic and the SIR model, with my estimated parameters Beta and Alpha. The initial conditions for the equations are defined at the beginning of my worksheet:

Hope someone can help me ;)





I'm running a 2D parameter sweep from Maple 15 on a MapleSim 5 model. The output is stored in a 2D matrix.  I've encountered two problems:

1) when I graph it with matrixplot the z-axis values are fine but I can't figure out how to change the x-axis and y-axis values from the matrix indices to the actual values of the swept parameters. 

2) When the parameter sweep begins I get a warning about storing the values in a matrix.  Maple...

I would like to know if it is possible to declare some variables in one parameter box (i would call it independ parameters) and other with parameters that depends on the first ones:





(for exemple)



hello boffins

if my de was soluble analytically, I would get an expression of time in terms of the other variables (V,theta,x) easily, but because it is only numerically solvable, i get an expression x(t)=proc(t)...,- the variables V and theta are mixed up in it-. Is there anyway they can appear?

I know I can put numerical values on V and Theta (and x) and solve for time (using parameters...

Hi all,

Is there a quicker way to find all unknows from an expression?

Say I want a list contains ALL parameters. In this case, it would return


Is there a way to do this?



Hi all,

Here is the problem, I will try my best to describe it:


Firstly of all,




In this system, the 'j' is a time varying parameter, and the...







Hi all,


After I loaded the package with(VectorCalculus), the output of vectors changed to a different one.

Is there any real "difference" when...

Please help me plot the graphs of the following equations:-

eq1 := diff(E[X(t)], t) = lambda-delta*E[X(t)]-beta*E[X(t)*V(t)];
 eq2 := diff(E[Y(t)], t) = -delta*E[Y(t)]+beta*exp(-rho*tau)*E[X(t)*V(t)];

eq3 := diff(E[V(t)], t) = gamma+N*kappa*E[Y(t)]-mu*E[V(t)]-beta*E[X(t)*V(t)]
NB:- E[X(t)]= the expected value of variable X at time t. 
Please help me know how to input this...

I have a differential equation having a parameter say 'a'.

If I increase 'a' by 10%, got change in the solution as well.

How to calculate change in percentage in the solution?.



     So I've got a numerical solution to a D.E. and want to find which parameters (v, theta) cause the second event to occur. Here's my dsolve

> soln:= dsolve({eqx, eqy, inty, intx, x(0)=0, y(0)=0}, {x(t), y(t)}, numeric, method = rkf45, output=listprocedure, parameters=[v, theta], events=[ [ [diff(y(t),t)=0, y(t)

 The first event is "Does the trajectory reach its max at a height less than 3.05m? If so, stop computation"...

Dear Maple users

Please help me correct this input:

> f := (c[A], c[B]) -> c[A]+c[B];
Error, invalid operator parameter name
f Assign Typesetting:-mambiguous(

(c[A]comma c[B]) rarr c[A] + c[B],

Typesetting:-merror(invalid operator parameter name))
In Maple, c[A] is actually "c subscript A".
Thanks for help.
PS: Is...


I have a system consisting of a multi-body system and various modelica/maple custom components. The problem is whenever I re-run the simulation even though all the simulation settings are same, the simulation results are inconsistent. There should be no difference between each simulation as all the parameters/settings are same. I am attaching two pictures which are both obtained from two successive simulations

Dear MaplePrimes,


I have a problem findning an explicit solution to an equation solve((P[h]-tau[h])*q[hf] = (P[f]-tau[f])*q[fh], [lambda[h]])]. Is you can see from my syntax, I have assumed a RealDomain and also that all parameters including the varialbe I'm solving for lambda[h] are positive, and also that lambda[h] is between 0 and 1. This is my syntax:


test := `assuming`([RealDomain:-solve((P[h]-tau[h])*q[hf] = (P[f]-tau[f...

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