## Can we convert expression into determinant...

Can we convert expression into determinant of 3 rows and 3 columns?

convert.mw

## v matrix in terms of u matrix...

Can we write v matrix in terms of matrix u? i.e., v=const*u.

uv_mat.mw

## How to solve system with one discrete variable?...

We have the system with one discrete variable along x-axis (i.e. 'i' is discrete in the attached file) and other variable 't' is continuous. But maple return error.

CD.mw

## Extract domain number...

Is there any command that allows me to extract the input number of any function f?

exmple:

f: (x1; x2;...;xn)-> y

command (f)=n

thanks for the help!

## Binary Recursive algorithm ...

I need to define a simple recursive algorithm (i'm not a programmer) such that:

xi=xi-1+b

with i=0,1,...,n;

and with all xi's elements of a Set A

how can i achieve this?

## differential system...

hallo every body

how do i solve this differential linear system with respect lambda is positive number

i use maple 18

Let the differential system with $\lambda>0$

$$\begin{array}{ccc} \dot{x}=y(t)\\ \dot{y}=z(t)\\ \dot{z}=-\lambda y(t)-h(t) \end{array}$$


prob.pdf

## Why maple return trivial solution after integratio...

Why maple return trivial solution after integration (see (11) in the attached .mw))? The result should be some non-trivial solution.

solutionsg.mw

## Relation between w and k...

I want to find the relation between w and k by putting Determinant(A) is equal to zero. Since the determinant is large (A is a matrix of size 6x6) and I am not able to find the simplified expression. How to do that?

determinant.mw

## Bifurcation of SEIR...

Hi,

Please can someone help me with a sample code for bifurcation? You can use parameter values for the parameters. I'm using maple 18. Below is my model:

 > restart:
 > f__1 := Delta -(psi + mu)*S(t);
 (1)
 > f__2 := psi*S(t) -(delta + mu)*E(t);
 (2)
 > f__3 := Delta*E(t) -(gamma+gamma__1 + mu)*X(t);
 (3)
 > f__4 := gamma__1*X(t)-(eta + xi + mu)*H(t);
 (4)
 > f__5 := xi*H(t) - mu*R(t);
 (5)
 > f__6 := gamma*X(t)-eta*H(t) - d*D(t);
 (6)
 > f__7 := b*D(t) - b*B(t);
 (7)
 > f__8 := phi__p + sigma*X(t)+eta__1*H(t) +d__1*D(t)+ b__1*B(t) - alpha*P(t);
 (8)

## Non-Linear System, fsolve fails to find a solution...

Non-Linear.mw

Hi, I have here a interesting non-linear system.

If I attempt to solve it using some specific form of the non-linear equations (form X*Y=Z) of the system, Maple (Verison 18) finds a solution.

But, if I replace some of them by some other forms (like form Y=Z/X), fsolve fails.

I usually use the non-quotient form. But is there any way to guide or configure fsolve to reach a solution?
I set up some of the regular options: placing a seed close to the solution, indicating intervals of possible solutions; but none of that works if I do not set up the non-quotient form of the equations. In some cases, fsolve does not reach a solution at all, no matter the form of the equations.

In the file, the equations that are causing the isssue are the last 3, those who start with the variable f1,f2 and f3.
I ran the system twice with both cases: non-quotient form and quotient form.

## PDETools:-pdsolve other solutions...

Given a set (list) of PDE, is there a way to search all possible solution sets? For instance, pdsolve will output the solution

{_eta[0](t, x) = 0, _xi[t](t, x, u) = _C1, _xi[x](t, x, u) = _C2, eta[1](t, x) = 0}

for the list of PDEs below. But I am aware that there is another solution different from the above, is there way to seek these other solutions?

[alpha*u^2*(diff(eta[1](t, x), t))+alpha*u*(diff(_eta[0](t, x), t))-u*(diff(eta[1](t, x), t))-u*(diff(eta[1](t, x), x))+u*(diff(eta[1](t, x), x, x, t))-(diff(_eta[0](t, x), x))-(diff(_eta[0](t, x), t))+diff(_eta[0](t, x), x, x, t), -(diff(_xi[x](t, x, u), u, u, u)), -(diff(_xi[t](t, x, u), x))-(diff(_xi[t](t, x, u), t)), -(diff(_xi[t](t, x, u), x, x)), -2*(diff(_xi[t](t, x, u), x, x))-(diff(_xi[x](t, x, u), x, x))+2*(diff(eta[1](t, x), x)), diff(eta[1](t, x), t)-2*(diff(_xi[x](t, x, u), x, x)), -(diff(_xi[x](t, x, u), t))*alpha*u-(diff(_xi[x](t, x, u), x, x, x))-(diff(_xi[t](t, x, u), x))+2*(diff(eta[1](t, x), x, t)), -(diff(_xi[x](t, x, u), x)), -(diff(_xi[t](t, x, u), t))*alpha*u+(diff(_xi[t](t, x, u), x))*alpha*u+(diff(_xi[x](t, x, u), x))*alpha*u+(diff(_xi[x](t, x, u), t))*alpha*u+eta[1](t, x)*alpha*u+alpha*_eta[0](t, x)+diff(_xi[t](t, x, u), t)-(diff(_xi[t](t, x, u), x, x, x))-(diff(_xi[x](t, x, u), x))-(diff(_xi[x](t, x, u), t))+diff(eta[1](t, x), x, x), -2*(diff(_xi[x](t, x, u), u)), -2*(diff(_xi[t](t, x, u), x, u)), -2*(diff(_xi[t](t, x, u), u))-(diff(_xi[x](t, x, u), u)), -(diff(_xi[t](t, x, u), u)), -(diff(_xi[t](t, x, u), u)), -5*(diff(_xi[x](t, x, u), u, u)), -(diff(_xi[t](t, x, u), u, u)), -3*(diff(_xi[t](t, x, u), x, u)), -2*(diff(_xi[x](t, x, u), u)), -(diff(_xi[t](t, x, u), u)), -(diff(_xi[t](t, x, u), u)), -2*(diff(_xi[t](t, x, u), u, u))-(diff(_xi[x](t, x, u), u, u)), -(diff(_xi[t](t, x, u), u, u, u)), -3*(diff(_xi[t](t, x, u), u, u)), -3*(diff(_xi[t](t, x, u), x, u, u)), (diff(_xi[t](t, x, u), u))*alpha*u-(diff(_xi[x](t, x, u), u))-3*(diff(_xi[t](t, x, u), x, x, u)), -2*(diff(_xi[x](t, x, u), x, u))-4*(diff(_xi[t](t, x, u), x, u)), -(diff(_xi[t](t, x, u), u))*alpha*u+(diff(_xi[x](t, x, u), u))*alpha*u+diff(_xi[t](t, x, u), u)-(diff(_xi[x](t, x, u), u)), -3*(diff(_xi[x](t, x, u), x, x, u))-(diff(_xi[t](t, x, u), u)), -7*(diff(_xi[x](t, x, u), x, u)), -3*(diff(_xi[x](t, x, u), x, u, u))]

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 (1)
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 (2)
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 (3)
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 (4)
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 (5)
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 (6)
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 (7)
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 (8)
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## limit and series...

Why solutions (5) and (6) are different? The solution (5) is obtained by putting f=0 of the series, while (6) is the result by taking limit at f->0.

check.mw

## how do i calculate this integral...

hallo evert body please how i do calculate this integral

in maple 18

ttp.pdf

int_{0}^{2\pi}(\cos^{i}(\theta)-\cos^{i+2}(\theta))d\theta