restart;
with(plots);
with(plottools);
with(DEtools);
N := S(t) + In(t) + C(t);
                    N := S(t) + In(t) + C(t)

eqn1 := diff*(S(t), t) = lambda - (lambda + sigma)*S(t) - (beta + Zeta)*S(t)*In(t) - beta[1]*S(t)*C(t), S(0) = ic1;
 eqn1 := diff (S(t), t) = lambda - (lambda + sigma) S(t)

    - (beta + Zeta) S(t) In(t) - beta[1] S(t) C(t), S(0) = ic1

eqn2 := diff*(In(t), t) = beta*S(t)*In(t) - (lambda + gamma)*In(t), In(0) = ic2;
 eqn2 := 

   diff (In(t), t) = beta S(t) In(t) - (lambda + gamma) In(t), 

   In(0) = ic2

eqn3 := diff*(C(t), t) = Zeta*In(t) + Zeta*In(t)^2 - (rho + lambda)*C(t) - Zeta*C(t)*In(t), C(0) = ic3;
                                                     2
     eqn3 := diff (C(t), t) = Zeta In(t) + Zeta In(t) 

        - (rho + lambda) C(t) - Zeta C(t) In(t), C(0) = ic3

lambda := 0.117852;
                       lambda := 0.117852

mu := 0.035378;
                         mu := 0.035378

beta := 0.11;
                          beta := 0.11

beta__1 := 0.05;
                        beta__1 := 0.05

g := 1;
rho := 0.1;
                           rho := 0.1

zeta := 0.02;
                          zeta := 0.02

sigma := 0.066;
                         sigma := 0.066

ic1 := 2390000;
ic2 := 753;
ic4 := 358500;
                         ic1 := 2390000

                           ic2 := 753

                         ic4 := 358500

dsol := dsolve([eqn1, eqn2, eqn3], numeric);
Error, (in dsolve/numeric/process_input) system must be entered as a set/list of expressions/equations
 

Hi all, how to get radical of expression?

Example: sqrt(a*(a+b+c))/(a*b+a*c+b*c) is 2, (a*b+a*c+b*c)*((1/3)*a+(1/3)*b+(1/3)*c)^(1/3) is 3

Thanks

I have this tedious looking function that I want to write in terms of the other expression but the command i usually use does not work here because the expressions are not polynomials. I am wondering if there is an alternative to doing this manually.
Temp.mw

As an example, the second display in the web site below shows the 42 possible triangulations of a cyclic heptagon polygon.

https://en.wikipedia.org/wiki/Polygon_triangulation

I have a document with quite a few symbols saved to my favorites palette. When I close the file and then reopoen it the Favorites Palette has not changed-the symbols are right where I want them. However, if I open the file with another computer the Favorites Palette is empty! What is happening?  (The document is stored in Dropbox and both computers are Macs running Maple 2023.)

How to solve this equation in symbolic form so that the resulting solution can be used as a formula in Excel?

Is it possible?

C = constant

I would like to use the forget command to make maple forget all the things it remembers in each iteration of the loop.

Could someone help me with that?

More details:  I use ansatz to try to solve systems of pdes. sometimes i put the ansatzs in a list and run a loop to try to solve the set of pdes for each ansatz. Sometimes this takes up a lot of memory and maple says kernel connection is lost.

Say I have a data matrix with one dependent variable and 50 independent variable

The first column is the dependent variable columns my first row has header names of variables say.

Is their way to code such that I can do a Linear regression stepwise such that even interactions terms can be into account and check for a best fit.

As only matlab can do it easily as i  see and it is paid costly software.

If pssible any help kind help. 

If possible some code can be written in maple kind help.

I have some large systems of linear equations.  The solutions are probability generating functions.  I can get solutions in a few minutes for systems of up to n= 200 eqns or so, but Maple just cycles indefinitely if I try to solve much larger systems.  I really only need to perform Gaussian Elimination, as I only need to solve for one of the n solutions.  The matrices are sparse, there are only 3 non-zero entries per row.  I tried to get help from the manuals but I get the impression that sparse solutions are only available for numeric computations.   Doesn't Maple allow for sparse symbolic solutions?  If so, how to do it?

What is the correct way to plot objects which have been created by the geometry library.

e.g. circle, point, line, e.g.

Download plotpoint.mw

Hi everyone
how can i overcome this error to solve this ODE ? tnx in advanced.

Download Hw.mw

Hallo every body 

i have a question How can be written this system of eqautions without the variable "t"

thanks 

Download problem.mw

how can be solved this system in maple 18

Download system.mw

Hi!

I want to implement to attached fortran program in Maple 2015 (the procudure starts at the end of the first page). 

localmin.pdf

The code does not seem dificult, but I don't know how to interpret the instructions "go to" of fortran. Reading Maple's doc about the "goto" instruction, I don't understand how to implement it.

Can somebody help with this code, please?

Many thanks in advance for your comments.

In the following I show two functions f and g where ShowSolution(Limit(..)) works for f but not for g. Any idea why?

with(Student[Calculus1]);

f := x^2 + x:
limit(f, x = -infinity);
infinity
ShowSolution(Limit(f, x = -infinity), maxsteps = 100);
// step-by-step solution is produced

g := x^2 + 3*x:
limit(g, x = -infinity);
infinity
ShowSolution(Limit(g, x = -infinity), maxsteps = 100);
Error, (in Student:-Calculus1:-ShowSolution) unable to compute solution steps

Maple is able to change f into an equivalent expression by factoring out x^2, but does not seem to be able to do it with g.

I attach two screenshots that show this curious behaviour.