Maple 2018 Questions and Posts

These are Posts and Questions associated with the product, Maple 2018

Is possible to solve this differential equation by maple?

thaks...

Hi,

I'm using the eBookTools package to convert a .mw file as a chapter into a PDF file. However, a problem arises when I convert a document with a few repeated plotting commands (such as plot(x^2)). The issue is that in the final PDF the images of the various plots overlap, and that the individual plots can't be clearly seen. Is there a resolution to this?

Thanks,
Bart

I'm trying to plot a graph of cos(2*theta)*omega*t+2*(sin(theta))^2*sin(omega*t)=0 in Maple (For values of theta between 40 and 88 degrees roughly, with a fixed value of omega). I have substituted x=omega*t and tried to solve, but as I'm sure you can tell it is not outputting the graph I'm after, I was hoping somebody would be able to tell me where I am going wrong. Thanks.

restart;
v := 145000;
thetavn := (1/6)*Pi;
omegac := .1;
s := cos(2*thetabn)*x+2*sin(thetabn)^2*sin(x);
plots:-implicitplot(s = 0, thetabn = 43*Pi*(1/180) .. 88*Pi*(1/180), x = -200 .. 200, tickmarks = ["piticks", "decimalticks"], gridrefine = 4, size = [800, 600]);

Is package SumTools supposed to be a superset of the sum command in Maple? Or is it supposed to be a complementary to it? When should one use SumTools vs. sum?

The help on SumTools says

The SumTools package contains commands that help find closed forms of definite and indefinite sums. The package consists of three commands and three subpackages.
 

But does not make it clear when to use it vs. sum or what is its relation to sum command.

I am asking because on one example, sum is able to give an answer, while SumTools can't. I have expected the other way, where if sum failed, then one will try SumTools.

restart;
sum(1/n*sin(n*x),n=1..infinity) assuming 0<x,x<Pi

SumTools:-IndefiniteSummation(1/n*sin(n*x),n=1..infinity) assuming 0<x, x<Pi

 

 

This should be simple but I am missing something. I want to sum the product of combinations of numbers.

I know I can assign values to a0...a[n-1]. But that isn't nice.

 

(n,k):= (5,4);
add(mul~(combinat:-choose([a(||)[](0..n-1)], k))) ; =a0*a1*a2*a3+a0*a1*a2*a4+a0*a1*a3*a4+a0*a2*a3*a4+a1*a2*a3*a4  which is correct.
add(mul~(combinat:-choose([(0..n-1)], k))) ;   #should be 24 but I get 0

 

Hello,

How I can remove this error.

also, i want to find answer via fsolve.

Error, (in fsolve) too many levels of recursion.

Thanks.

test.mw

Some definition of n! where n are the negative integers is taken to be infinity. (this is Gamma function for negative integers).

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

So 1/(-1)!  should be zero. And that is what Mathematica gives

But Maple does not like (-1)!, it gives division by zero, I assume because it is not using the above definition using Gamma function.  But then how come Maple is able to find correctly this sum

sum(1/factorial(n-1),n=0..infinity)

Which is exp(1).   The first term above, when n=0 is   1/(-1)!  which Maple does not like. Because if we take the first term as 1/infinity=0 then the sum is the same as if we had

sum(1/factorial(n-1),n=1..infinity)

And now it is exp(1) with no problem dealing with negative integer factorial.

Question is: Since Maple does not like negative integer factorial, how comes it accepted the above sum, whose first term contain negative integer factorial? 

Just wondering how it did the above, that is all. When I solved this by hand, I used 1/(-1)! = 0 to be able to sum it.

I have converted a single large worksheet into a workbook comprising many worksheets.  One of the worksheets contains start-up code.  Is that start-up code (which includes numerous subroutines/functions) automatically available/accessible/executable by all the other worksheets in the workbook?  

Melvin

 

I have this animation that displays a particle's position after reflection from a shock (the blue plane). I want to add a line that shows the particle coming in and reflecting and have them animate sequentially, but I cannot figure out how. The line should travel along the b axis, but offset in the xi axis to end where the helix begins. Here is the code for the helix animation:

 

restart; with(VectorCalculus); with(Student[LinearAlgebra]); with(plots);
v[i] := 145000; thetabn := (1/8)*Pi; thetavn := (1/6)*Pi; k := 10; omegac := .5;
v[b] := cos(2*thetabn)/cos(thetabn); v[g] := sin(2*thetabn)/cos(thetabn);
n := `<,>`(k*cos(thetabn), k*sin(thetabn), 0);
vr:=
[v[b]*t, v[g]*sin(omegac*t)/omegac, v[g]*cos(omegac*t)/omegac];

lambda := v[i]*cos(thetavn)/cos(thetabn);
shockplot := PlanePlot(n, caption = "", planeoptions = [colour = blue, transparency = .5], normaloptions = [shape = cylindrical_arrow, colour = red]);

t1 := textplot3d([k*cos(thetabn), k*sin(thetabn), 0, 'n'], align = above);

display(plots[animate](plot3d, [[v[b]*t, v[g]*sin(omegac*t)/omegac, v[g]*cos(omegac*t)/omegac], t = 0 .. x], x = 0 .. 6*Pi, axes = normal, colour = red, labels = ["b", zeta, xi], thickness = 2, paraminfo = false), shockplot, t1, scaling = constrained, tickmarks = [0, 0, 0]);

 

Hello pdsolve experts:  

Using Maple 2018.2.1 and Physics 292 on windows 10.

pde := diff(w(x,y),x)+ (arccot(x)^n *y^2 + y-  arccot(x)^n )*diff(w(x,y),y) = 0;
pdsolve(pde,w(x,y));

When I try

PDEtools:-charstrip(pde,w(x,y))

It does not generate error.

Should pdsolve have generated this error message instead of returning no solution?

 

The program was written in 2004 with maple 6. Now i'am working by maple 18. And i did'nt launch the program. painleve_test.zip

Thank you for your interest in advance.

Hello my friends

I want to solve first order non-linear differential equation by maple 2018 but it does not give me the explicit form for a(t) as the function of time t.

this is my equation where z,k,c, and w are non zero constants 

3*a(t)-a(t)^2-3*z*(diff(a(t), t))^2+k*c*a(t)+w/a(t) = 0

please guide me.

with the best regard

Hi

I would like to designate AU as currency for my application, rather than the USD.

I can do it to a degree, but when I use combine I have problems. Compare output 8 and 9 to 17 and 18. help?

 

CURRENCY.mw

This is from the documentation of ?plot3d,light:

 

light=[phi, theta, r, g, b]

    This option adds [my emphasis] a directed light source

    from the direction phi, theta in spherical coordinates.

 

The "adds" in that sentence seems to imply that

multiple light sources are possible, but it does not seem

to work that way.  Each subsequent light option overrides

the previous one as we see in the following illustration

where we render a ball three times by illuminating it

(a) from the north, (b) from the south, and (c) from

both the north and south.  In (c) Maple accounts for only

the south light.

restart;

with(plots): with(plottools):

ball := sphere(1, style=surface, color=gold):

display(<
    display(ball,light=[0,0,1,1,1])   |
    display(ball,light=[180,0,1,1,1]) |
    display(ball,light=[0,0,1,1,1], light=[180,0,1,1,1])
 >);

 

Download light.mw

 

This is using Maple 2018.2.1 and using Physics version MapleCloud 289 on windows 10, 64 bit with lots of RAM (64 GB). The call to timelimit hangs. Is there a workaround?

restart;

#and in new execution cell

pde :=  diff(w(x,y),x)-((k+1)*x^k*y^2- a*x^(k+1)*tan(x)^m*y + a*tan(x)^m )*diff(w(x,y),y) = 0;
cpu_time := timelimit(180,CodeTools[Usage](assign('sol',pdsolve(pde,w(x,y))),output='realtime'))

 

 

 

 

5 6 7 8 9 10 11 Last Page 7 of 34