How to find infinitesimals of a system of pdes? I can find out for a single pde but not able able to solve for system of pdes with several dependent and independent variables. Can anyone please provide me the code for that or give some clue. Thanks

I have a task. Draw a cylinder of a certain diameter and length. And there is a table of values with points inside this cylinder. How to display the points inside the cylinder (the table of values has 3 parameters - angle (sin (a)), radius (R), length?

I am trying to do fsolve in a range (-7..14), however, it gives no solution.

But when I solve the same equations with solve (after removing all the Imaginary solutions), I get two results, one of them is in the range (-7..14). 

I even expanded the range of fsolve, say (-10..20), but still got no solution...

This is just getting weirder and weirder. Attached kindly find the Maple file, note that the first solve takes about 1 minute (on my laptop: CPU i7 + MEM 8G + SSD).

fsolve_In_Range.mw

Hello,

i have a Problem with maple. I have written this simple procedure

myPi_1:=proc(r)
local i,l;
l:=0;
for i from 1 to floor(r) do
    if isprime(i) and (i mod 4 = 1) then
        l:=l+1;
    end if;
end do;
return l;
end proc:    

When i use it like this 

k := myPi_1(80);

it works

But when i triy to plot it

plot(myPi_1(t), t = 0 .. 500, numpoints = 500, thickness = 2, color = black);

i get this message
Warning, expecting only range variable t in expression myPi_1(t) to be plotted but found name myPi_1

And no plot

Thank you for any Help

I want to calculate the following integral numerically with required precision.

First, the functions are defined:

G1:=-0.9445379894;
f:= (x) -> 0.9/abs(x-0.4)^(1/3)+0.1/abs(x-0.6)^(1/2);
U1 := unapply(-exp(-x)*(evalf(Int(f(t)*exp(t), t = 0 .. x))+G1)/2-exp(x)*(evalf(Int(f(t)*exp(-t), t = 0 .. x))+G1)/2, x);
U:= unapply(-exp(x)/2*(evalf(Int(f(t)*exp(-t),t=0..x))+G1)+exp(-x)/2*(evalf(Int(f(t)*exp(t),t=0..x))+G1), x);

Next, I calculate the integral in numerical form:

evalf(Int(U1(x)^2+U(x)^2-2*f(x)*U(x), x=0..1, digits=4, method = _Gquad));

If I specify digits=4, Maple return the answer -0.4291

If I use digits=5 or larger, Maple return someting like this

Is it possible to increase precision of calculation?

Please help me on this :

Download untitle_2_(1).mw

Download FINAL_RESULT.mw

To select a piece from a list, for example:

lst:=[1,2,3,4,5,6]

I want to get the list piece from second place to fifth place: [2,3,4,5].

Is there a function?

Thanks

How do cylinder (3D plot) from Excel file(csv)?

I have table in the Excel:

Angel(A)  length(cylinder) Function(sin(A)*EXP(1-L/1000)

1                 5                          0,05

2               10                          0,1

......

360         1000                      0

Please help me..

Hi,
I don't understand how contourplot chooses it's view range. I would like a contour plot to go from r=0..10 and display axes from [-10..10, -10..10].

plots:-contourplot(r*sin(phi), r = 0 .. 10, phi = 0 .. Pi, coords = spherical, grid = [80, 80]);

doesn't produce a plot with range [-10..10]. Adding view doesnt compute anything differeently, just makes the axes bigger.plots:-

contourplot(r*sin(phi), r = 0 .. 10, phi = 0 .. Pi, coords = spherical, grid = [80, 80], view=[-10..10,-10..10]);

I want more contour lines near the endpoints of the range. why is it focused in the middle?

any help is appreciated, 

Thanks!

Hi everyone,

I am making a model of the solar system (not to scale) in Maple for a school project. I need to add an animation to make the planets move on the orbits I have for each of them. How do I do this?

I uploaded pictures on a Photobucket account of how I've done it so far to help. This is my first time using Maple so I know that I probably did some things inefficiently. 

Photobucket URL: http://i1070.photobucket.com/albums/u492/nmsnyder007/Capture1_zpsfmitm0ou.jpg

Thanks :)

I have a program:

Running abb(1,3) gives error: Error, (in abb) illegal use of a formal parameter

Might be a silly question: Is it not allowed? Do I have to define a local variable for b in order to change it?

Hey there!

this is the formula:

diff(ca(t), t) = -3.600000000*10^20*exp(-15098.13790/(340-20*ca(t)))*ca(t), ca(0) = 2

I can easily plot it by solving DE numerically, however I can't seem to find a way to determine what 't' is at ca(t)=0.2

thank you so much in advance!

Kind regards, 

Gerard 

Download 2222222222222222222.mw

> restart; 
> A[0] := 10^(-3); a := 10^5;
> sys := diff(R(theta), theta) = A[0]*exp(2*mu(theta))*sin(theta)/(2*a), R(theta) = 2*exp(-2*mu(theta))*(1-(diff(mu(theta), `$`(theta, 2)))-cot(theta)*(diff(mu(theta), theta)));
> cond := R(0) = 10^(-5), mu(0) = 118.92, (D(mu))(0) = 0;
> F := dsolve({cond, sys}, [R(theta), mu(theta)], numeric);
> with(plots);
> odeplot(F, [theta, R(theta)], 0 .. 3.14, color = black, thickness = 3, linestyle = 4)
> odeplot(F, [theta, mu(theta)], 0 .. 3.14, color = blue, thickness = 3, linestyle = 1)

After last two lines maple writes:

Warning, cannot evaluate the solution past the initial point, problem may be complex, initially singular or improperly set up

And gives me empty plots. I can't figure out where an error can be. Some things I noticed:

Maple doesn't calculate the system before and after zero. If I change the range from 0..3.14 to -10..10 or to 0.00001..0.00001, it gives me 2 errors for 1 plot.

Also if I change the condition mu(0) = 118.92 to mu(0) = 1 or mu(0) = 50 or mu(0) = 80, it works. After ~80 it gives an error. I can't imagine where could appear a division by 0 or some other mistake.

Hello People in mapleprimes,

I have a question about collecting part of expression.
Please teach me an answer to this.

I want to modify a1 to b1.


e3.mw

Thanks in advance.