## Add straight line animation to existing animation...

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]);

## pdsolve generate error PDEtools:-charstrip charstr...

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?

## How can i run the program written by maple 6?...

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

## first order non-linear differential equation...

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

with the best regard

## Currency convention...

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

## How to specify multiple lights in plot3d?...

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])  >);

## timelimit does not work on some problems...

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'))
```

## Problem using with(CodeGeneration)...

Hello,

I'm a long-time Maple user and have used the CodeGeneration package in the past, but with a recent download of Maple 2018, I'm now getting an error I have never gotten before. Even when I do something simple (see below, for example), I get an error that reads "Error, (in clear) argument `` is incorrect or out of order". And I get this error no matter which language I choose. Any help would be much appreciated.

> with(CodeGeneration)

> R(exp(x))

Thanks!

## Workbook mode, variables...

I hope you can help me. I like to use the Workbook feature in Maple 2018. I save variables in one document to use them in another document as well. If, however, the value of the variable changes, I have to delete the variable in the variable manager each time and save it again.
Is there a command I can use to delete and re-save the saved variables?

## Why is Maple registering &t as a neutral operator ...

Hey,

I have just started using Maple for my university project and I am follwing this guide https://www.maplesoft.com/support/help/maple/view.aspx?path=DifferentialGeometry%2FTensor%2FKillingVectors to calculate Killing Vectors. My issue is that when I try and define a metric using evalDG, I need to write dx&tdx to mean the tensor product between the two. Maple interperates this as a neutral operator and gives me "Error, invalid neutral operator".

I am not sure where the issue is as I have written exactly the same code as the guide and yet it gives me an error 3 lines in. Is there some issue that I am not aware of as someone who hasn't used Maple before? Any advice would be useful as I am not really sure how it is possible and I need to be able to write the tensor product to define the metric.

Even for the simplest metric it does not work. My code is:

with(DifferentialGeometry): with(Tensor): with(LieAlgebras):
DGsetup([x, y], M):
g1:=evalDG( dx&tdx):

Any help would be greatly appreciated.

## how I can find solutions for non linear equations ...

how I can find solutions for non linear equations.

I want to find non zero solution.

thank you

ZAH.mw

Maple Worksheet - Error

Failed to load the worksheet /maplenet/convert/ZAH.mw .

## Error, invalid input: unknown uses a 1st argument,...

Hi, Maple is totally new to me and I found something confusing.

Here is what I have:

the_first_element:= proc( A:: Array( numeric ) ) ;
A[1];
end proc():

And it shows Error, invalid input: unknown uses a 1st argument, A (of type Array(numeric)), which is missing.

But in another similar procedure, I have exactly the same lines but it goes without error.

locate_max := proc( A :: Array( numeric ) )
if ArrayNumDims(A) <> 1 then
error "can only search 1d arrays"
end if:
end proc:

I have no idea what is wrong with these 4 lines.

## MapleCloud: The account type or email address or p...

I am on a Mac and unable to login to MapleCloud. I can log in perfectly fine via the website in all browsers. Any solutions for this?

How to simplify

a*b=a*c

to b=c ?

## why is a procedure changing the input?...

I have a procedure that changes the value of an input variable quite unexpectdly. Can anyone explain why? I have a very simplified example of this below.

restart;
with(LinearAlgebra):
switch := proc (V::Vector)
description "This procedure is supposed to take a Vector V and switch entries 1 and 2";
local W,a,b;
W:= V;
a:= W[1];
b:= W[2];
W[1 ] := b;
W[2] :=a;
W
end proc;

V1:=Vector([1,3,5]);
V2:=switch(V1);
I have omitted the output for brevity's sake but all works well as expected.
However,
V1;

returns V2 not V1. Why is the procedure changing V1?

The problem occurs with matrices but not with lists.

Thanks.

 First 8 9 10 11 12 13 14 Last Page 10 of 37
﻿