In Kitonums'answer of

http://www.mapleprimes.com/questions/220229-How-Do-I-Solve-A-Differential-Equation-In-Maple

I read a code of remove(t->t=".", b);
t->t="." is a Boolean-valued procedure.

But, then, why does (t->t=".")(9); not return false like (t->t^2)(3); returns 9?
How can I have maple return false?

Thanks in advance.

I have solved a BVP using finite difference method in maple. But the comparsion with the dsolve solution shows big difference,

Why there is too much difference? Is there an elegant way to implement FDM?

FDM_Dbvp_sheet_1.mw

i wrote a procedure for determine a lambda symmetries and first integrals of ODEs.

Procedure is running but commands is getting error.

Can  anybody help me.

Thanks in advance. procedure.mws

If a particle that moves in only one dimension is subject to a force Fi between the time

steps ti and ti+1, the velocity vi and position xi of the particle is:

v[i] := v[i − 1] +(1/m)*F[i]*Δt

x[i] := x[i − 1] + 0.5 (v[i − 1] + v[i])                   

Use the mean of v between ti and ti+1 when updating xi, since the value may change

a lot from step to step. In the subsequent, we set the mass m = 1 and the time steps

are Δt = 1, since we could absorb m and Δt in the expression for the force Fi anyway.

Write a procedure that computes xi and vi for a particle subject to random forces Fi,

uniformly distributed on the interval [-0.5..0.5].

I`ve written a procedure that generates random forces (F[i]) in the given interval. How can I write a for – procedure that computes x_i and v_i ?

For exaqmple, the quadratic equation w^2 + uw + v = 0 corresponds to the deter minant

| -u  1  1  |

| v    0  1  |  = 0

|w^2 w w-1|

Is there any way to find a determinant corresponding to an equation, as above?

This is an issue in the preparation of a nomograph for the initial equation.  

It is generally solved by trial and error.

hi

i want save result in text file?

how i can do it?

for example eta and F(eta) in two  column

sample file is attache.

printf.mw

txtop1.txt

sample for save results::::

eta                     F(eta)

0.00000000, 0.00000000
0.10000000, 0.00096663
0.20000000, 0.00373543
0.30000000, 0.00810907
0.40000000, 0.01388926
0.50000000, 0.02087683
0.60000000, 0.02887169
0.70000000, 0.03767307
0.80000000, 0.04707963
0.90000000, 0.05688968
1.00000000, 0.06690139

Download txtop1.txt

Hi

I need help to write a procedure that uses Maple`s built-in rand() - function to generate uniform random floating point numbers between -r and r, where r is an input parameter of the procedure.

>M:=600;

>R1:=rand(0..1):   R2:=() -> 2*R1()-1:       
>for i from 1 to M do
    f[i]:=R2()*rand()/10.^12:
  end do:

With this procedure I get random floating point numbers (+/-), but I can`t figure out how to generate numbers between +/- a parameter (in this case r).

If anyone could help me understand how to get this to work I would be very gratefull.

Greetings!

Strange things happen with the "Explore" command! Let's say I want to plot the function F(x)= a*x. When I am writing:

>Explore(plot(a*x,x=0..10),parameters=[a=0..2]) ;

everything is OK, but when I use:

>F:=a*x;
>Explore(plot(F,x=0..10),parameters=[a=0..2]) ;

the initial frame is correct but when I try to move the parameter cursor, the plot dissapears. 

Any ideas what is wrong and how I can fix this?

I would like to plot a function u(r,theta,z) where r, theta, and z are standard cylindrical coordinates.  I would like u to be illustrate on the domain (say the unit cylinder) by a color scheme, say blue = minimum and red = maximum value of u.

Does anyone have any ideas how I could do this?

Heather

Hello, 

I loaded Maple to my friend's PC. But we can not execute any command in worksheet. When we write some lines and hit enter, it does not respond in anyway. (excluding simple calculations such as: 2+3 etc.) What is the problem and how can we solve it? 

PC: Windows 10 

Maple 2016.1

G := 6.6743*10^(-8);

a := 1.9501*10^24;

b := .3306;

c := 2.99792458*10^10;

d := 2.035;

pi := 3.143;

eps := 3.8220*10^35;

g(r) = 1-s(r)/0.06123;

j(r) = e^(-(1/2)*w(r))*(1-2*G*v(r)/(r*c^2))^.5

sys := diff(v(r), r) = 4*pi*r^2*eps/c^2, ics=v(0)=0

diff(u(r), r) = -G*(eps+u(r))*(v(r)+4*Pi*r^3*u(r)/c^2)/(c^2*(r^2-2*G*r*v(r)/c^2)),u(0)=1.3668*10^34

diff(w(r), r) = 1.485232054*10^(-28)*(v(r)+4.450600224*10^(-21)*pi*r^3*u(r))/(r^2-2*G*r*v(r)/c^2), conditions: w(0)=0,iterate it to find w(688240)=-2.05684, it solve must satistfy the both conditions.

diff(r^4*j(r)*(diff(g(r), r)), r)+4*r^3*g(r)*(diff(j(r), r)) = 0, conditions dg(r)/dr =0  at r=0, g(688240) =0.87214

diff(J(r), r) = (8*pi*(1/3))*(eps/c^2+u(r)/c^2)*(g(r)*j(r).(r^4))/(1-2*G*v(r)/(r*c^2)) condition J(0)=0.

Hi everybody,
 

I write a worksheet which contains thesimple code provided in ?Maplets[Button] :

with(Maplets[Elements]):
maplet := Maplet(["Select one:", ......]) 
Maplets[Display](maplet):

As mentioned in ?MapleViewer it is possible to export a worksheet in a .maplet file (I use Windows 7) and to execute it by double clicking on the corresponding icon.
I proceeded as explained in the help page
But double clicking does not work with me : a "User Interface Customization System" window opens and shuts after a few seconds without displaying the expected maplet 

(right click + open with and select mapleviewer.exe shows that mapleviewer.exe does exist, so the issue does not likely come from an incomplete Maple installation).

I tried a few variants of the worksheet, such that
with(Maplets[Elements]):
Maplets[Display](Maplet(["Select one:", ......])  ):
or even
Maplets[Display](Maplet(["Select one:", ......])  ):

But it keeps getting bad
Could you please help me to fix this ?

TIA

hi

please help me for solve differential equations

6.mw
 

Download 6.mw

Dear 

Hope you will be fine. My file takes to much time to solve the system of nonlinear algebraic equations for Iterations=8. please solve my problem I will be waiting for positive response.

Error_graph.mw

How do I solve a differential equation in maple? Is there a specific identity that you can use?