Just a quick question, I know we can use "%" to obtain the las result in maple. what if I want to obtain the second last result? or in general the n-last result ? Thx

Hi, I'm trying to solve 1-D thermal equation defined below, but I end up with an error : Error, (in pdsolve/numeric/process_PDEs) PDEs can only contain dependent variables with direct dependence on the independent variables of the problem, got {f(t, 1)}.

Could you please point out what am I doing wrong? Perhaps it's how I define the PDe or how I write the boundaries? Any help appreciated!

with(PDEtools)

PDE := cp*diff(T(t, r), t) - k_1*diff(diff(T(t, r), r), r) - k_1*diff(T(t, r), r)/r = Q;

all variables for now have dummy values of 1     

cp := 1;
k_2 := 1;
A := 1;
k_3 := 1;
k_4 := 1;
k_5 := 1;
k_6 := 1;
T_amb := 1;

bcs_1 := eval(diff(T(t, r), r), r = 1) = k_3*T_amb;

bcs_2 := eval(diff(T(t, r), r), r = 0) = 0;
 
bcs_3 := eval(diff(T(t, r), t), t = 0) = 25;

PDE_all := {PDE, bcs_1, bcs_2, bcs_3};

sol := pdsolve(PDE_all, numeric);
Error, (in pdsolve/numeric/process_PDEs) PDEs can only contain dependent variables with direct dependence on the independent variables of the problem, got {f(t, 1)}
 

Int not working with GlobalSolve why? It shows that bounds should be specified to all variable. but i have given bounds to all variables already. Thank you

How do I solve an overdetermined system of algebraic equations in Maple? solve command returns trivial solution for variables which are not actually trivial when I solve them by hand.

Hi all

When I solve using maple the first-order differential equation: diff(y,x)=0  for x in the closed interval [0,1] we obtain a constant function as a solution

but one can define the piecewise constant function see please the attached code

diff_piecewise.mw

why when we differentiate the piecewise function gives undefined derivative at point zero and a half.

Whats is the relationship between this example and Existence and uniqueness theorem for fist order ode

Many thanks

Hello everybody,

While i was trying to work on a physical math problem, a system of 4 integral equations is obtained. The right hand sides of these equations are known functions of r. The left hand sides contain double integrals with respect to lambda and t. i believe that an analytical determination of the 4 unknown functions f_1(t), f_2(t), f_3(t), and f_4(t) is far from being trivial, thus recourse to a numerical technique is necessary and indispensable.

i tried to express the unknown functions as series expansions in t and solve the resulting linear system of equations for the expansion coefficients, but unfortunately the coefficients are very large and the solution is strongly dependent on the number of coefficients. i was wondering whether someone here has some experience with such integral problems and is willing to assist and help. Any hint is highly appreciated.

i attach a Maple script including the equations.

Thank you,

>>>>>> Question.mw

I am trying to use Maple to solve a set of 5 equations, but cannot get a solution. Or there is no solution??

Any help? (Yes, the L function is a likelihood function and I am doing MLE for 5 variables..)

Download PlayGround.mw

Please, is it possible to enlarge the vertices of a graph (DrawGraph in GraphTheory)? Thanks

Hi there, 

I am trying do to a solve procedure, so you can solve an equation using the following argument. 

Solution(eqn, value, var) which uses the embedded solve command. 

When is an integer it works fine with this code here. 

MySolution:=proc(xl::algebraic,is::integer, x::algebraic)
return solve(xl=is,x);
    end proc; 

However the problem arises when I will like to make it to recognize is a an decimal number aka float. 

MySolution:=proc(xl::algebraic,is::integer, x::algebraic)
    return solve(xl=is,x);
    if type(is,float) then
return solve(xl=is,x);
    end proc; 

Any idears on what I am doing wrong? 

Many thanks in advance and have a nice day.

I would like to find a fixed point of f^4 in tems of a and b. I define function as

I calculate f(f(f(f(x,y))))  and Iet f(f(f(f(x,y)))) = (x,y), then use the solve command as:

solve({b^4*(a*(a*(a*x-x^2-x*y)-(a*x-x^2-x*y)^2-(a*x-x^2-x*y)*b*x*y)-(a*(a*x-x^2-x*y)-(a*x-x^2-x*y)^2-(a*x-x^2-x*y)*b*x*y)^2-(a*(a*x-x^2-x*y)-(a*x-x^2-x*y)^2-(a*x-x^2-x*y)*b*x*y)*b^2*(a*x-x^2-x*y)*x*y)*(a*(a*x-x^2-x*y)-(a*x-x^2-x*y)^2-(a*x-x^2-x*y)*b*x*y)*(a*x-x^2-x*y)*x*y = y, a*(a*(a*(a*x-x^2-x*y)-(a*x-x^2-x*y)^2-(a*x-x^2-x*y)*b*x*y)-(a*(a*x-x^2-x*y)-(a*x-x^2-x*y)^2-(a*x-x^2-x*y)*b*x*y)^2-(a*(a*x-x^2-x*y)-(a*x-x^2-x*y)^2-(a*x-x^2-x*y)*b*x*y)*b^2*(a*x-x^2-x*y)*x*y)-(a*(a*(a*x-x^2-x*y)-(a*x-x^2-x*y)^2-(a*x-x^2-x*y)*b*x*y)-(a*(a*x-x^2-x*y)-(a*x-x^2-x*y)^2-(a*x-x^2-x*y)*b*x*y)^2-(a*(a*x-x^2-x*y)-(a*x-x^2-x*y)^2-(a*x-x^2-x*y)*b*x*y)*b^2*(a*x-x^2-x*y)*x*y)^2-(a*(a*(a*x-x^2-x*y)-(a*x-x^2-x*y)^2-(a*x-x^2-x*y)*b*x*y)-(a*(a*x-x^2-x*y)-(a*x-x^2-x*y)^2-(a*x-x^2-x*y)*b*x*y)^2-(a*(a*x-x^2-x*y)-(a*x-x^2-x*y)^2-(a*x-x^2-x*y)*b*x*y)*b^2*(a*x-x^2-x*y)*x*y)*b^3*(a*(a*x-x^2-x*y)-(a*x-x^2-x*y)^2-(a*x-x^2-x*y)*b*x*y)*(a*x-x^2-x*y)*x*y = x}, {x, y})

My computer was freezing. How can I get my result. Thank you

How would I solve a linear algebra differential equation with initial conditions.

For example, what if I had:

x'(t) = [1 2 ; 3 4] x(t) such that the ics: (0,1)

I try to write a Maple Code. But I can' t finish it. 

This is very important for me. Could you help me? download_Maple Code.mw

I am using foslve to get the numerical solution of a very complex equition. When I rerun the code with different Digits settings, I got different solutions. I guess it is not surpprising since it is a numerical solution, but how can I trust/choose which one to use?? Is there anyway to unify the solutions regardless the Digits settings.

This attached are when Digits:=30 and Digits:=20 respectively.. Note, the K is a very large nubmer.. the X is a beta distribution..

Hi guys, 

I have tried to create a loop to solve a set of two equations, but can't seem to get it working. My initial equations are given by;

nstar := (F, L, sigma) -> ceil((ln(k*F) - ln(c(L, sigma)*B))/ln(Phi(L, sigma)))

and 

i := (F, L, sigma) -> r*(1 - (G(L, sigma)*Phi(L, sigma))^nstar(F, L, sigma)*B/F)/(1 - G(L, sigma)^nstar(F, L, sigma))

in which both are based on further rather simple equations. To these I am trying to apply the proc function where I am trying to find which i makes borth the equations above work :

i := proc(F,L,sigma)  

local k :=0.01 ;  

local eps := 0.01 ;  

do while(eps>0.001)  

nstar:= (6)

i := (7)

eps:= i -k:

k=i:

end do;

k;

end proc;

Error, Got internal error in Typesetting:-Parse : "'_Inert_DELAYLESSTHAN' is not a valid inert form"
 

But as you see I am here getting a error which I have not managed to fix. Can anyone see where I might have gone wrong? Could this be done by solve or fsolve? If yes, then how (have tried it as well without succeding)?

help me! 

I have a problem with the system, looking forward to everyone's help!