hi friends

i have a problem in maple with an error

dx := diff(x(t), t, t) = -G*Mz*x(t)/(x(t)^2+y(t)^2)^(3/2):

dy := diff(y(t), t, t) = -G*Mz*y(t)/(x(t)^2+y(t)^2)^(3/2):

 G := 6.67*10^(-11); Mz := 6*10^24:
 IniC := x(0) = 7*10^6, (D(x))(0) = 0, y(0) = 0, (D(y))(0) = 9*10^3:
 Digits := 15:
 Ns := dsolve({dx, dy, IniC}, {x(t), y(t)}, numeric):
 dsnumsort(Ns(0), [x, y]);

>for i from 0 to 400 do T := 40*i; NsT := Ns(T); X[i] := rhs(NsT[C1]); Vx[i] := rhs(NsT[V1]); Y[i] := rhs(NsT[C2]); Vy[i] := rhs(NsT[V2]); MofI[i] := X[i]*Vy[i]-Y[i]*Vx[i] end do:

> with(plots);
> p1 := polarplot(6378*10^3, phi = 0 .. 2*Pi);
> p2 := plot([seq([X[i], Y[i]], i = 0 .. 327)], thickness = 2);

display({p1, p2}, labels = ['x', 'y'], scaling = constrained);

but i see and I I can't draw PLOT:

Error, invalid input: rhs received [t = HFloat(0.0), x(t) = HFloat(1.0), diff(x(t), t) = HFloat(0.0), y(t) = HFloat(0.0), diff(y(t), t) = HFloat(1.0), z(t) = HFloat(0.75), diff(z(t), t) = HFloat(0.0)][C1], which is not valid for its 1st argument, expr

can you helpe me?

I'm a student using Maple 18.

I'm still having some navigation issues with the Maple text editor. I realize that being in "math" mode or "text" mode causes Maple to interpret an <enter> key press differently.

However when I paste in some text, I get unexpected behavior. 

My professor will assign a list of problems, and I will paste them into Maple so it looks similar to this

1.) solve math problem 1

2.) solve math problem 2

....

Then I go to problem one, put my cursor at the end of the line and push <enter> hoping to make some room between problem 1 and 2 for my work. When I do this, the cursor jumps to the end of the list I had just pasted into the document.

How can I insert new blank space between the listed problems? I've had the same experience pasting in from MS word or just plain notepad.

Right now the only solution I've found is to copy the listed problems into maple 1 at a time.

Thanks in advance for any suggestions.

Brent

Hello
There is some kind of strange behaviour with copying/pasting maple code from IDE to some text editor. Namely, the code collapses into one long line in text editor. Is it OK with Maple IDE?

I found this problem in a book about mathematica.
I want repeat it with maple.
But even Digits=1400, the exact value of s@x=70 is still different with the result(0.633319) on that book.
How to resolve this problem?
I want some help.

code:
restart;
Digits:=1400:
p:=convert(series(cos(x),x,201),polynom):
s:=add(op(i,p),i=[1,2,3,-1,-2,-3]);
add(evalf(coeff(p,x,i))*70^i,i=[200,198,196])+add(evalf(coeff(p,x,i))*70^i,i=[2])+add(evalf(coeff(p,x,i))*70^i,i=[4]);
#plot(s,x=0..40,view=[0..40,-2..2],numpoints=6000,gridlines,style=point);
simplify(eval(s,x=70));
evalf(%);

Dear all
I am using Physics[Vectors] package of Maple 17. I want to define an orthogonal curvilinear coordinates through alpha and beta independent variables. To define unit vectors of alpha and beta, I have to apply the derivatives of position vector r_ with respect to alpha and beta, respectively. Please help me to define the unit vectors in directions alpha and beta as derivatives of position vector r_ with respect to alpha and beta, respectively. Please see the below Code:

> restart;

> with(Physics[Vectors]);

> Setup(mathematicalnotation=true);

> r_:=X(alpha,beta)*_i+Y(alpha,beta)*_j+Z(alpha,beta)*_k;

The unit vectors in directions alpha and beta should be defined as:

_alpha=diff(r_,alpha)
_beta=diff(r_,beta)

It is worthwhile to mention that the following expression governs:

> diff(r_,alpha).diff(r_,beta)=0;

Please guide me.

Best wishes

Ali

Hey Guys, 

I was wondering how big an algebriac equation has to be before maple crashes. (i cant think of a better word) . I am trying to derive an epression that involves solving 9 equations that all pretty big. about 16 terms. I am substituting in each equation into the next and I get to the last one and it just says evaluating. I left it up overnight and it was still there evaluating. Any help would be appreciated. 

Help me with this:

I have a differential equation:  s:= diff(h(t),t) = -0.1738137398e-2/sqrt(2.8-h(t))

Solution is: h(t) = 14/5-(1/100000000)*2607206097^(2/3)*t^(2/3), h(t) = 14/5-(1/100000000)*(-(1/2)*2607206097^(1/3)*t^(1/3)-(1/2*I)*sqrt(3)*2607206097^(1/3)*t^(1/3))^2, h(t) = 14/5-(1/100000000)*(-(1/2)*2607206097^(1/3)*t^(1/3)+(1/2*I)*sqrt(3)*2607206097^(1/3)*t^(1/3))^2

And i have to need a plot... so i use complexplot and recive a mesage:

Error, (in plots:-complexplot) invalid input: `plots/complexplot` expects its 2nd argument, r, to be of type {range, name = range}, but received h(t) = 14/5-(1/100000000)*(-(1/2)*2607206097^(1/3)*t^(1/3)-((1/2)*I)*3^(1/2)*2607206097^(1/3)*t^(1/3))^2

Help me if you can!! Thank you so much!!! 

Dear,

I have a perfectly working when all parameters are known (figure 1), however I want to perform a sensitivity analysis by derivating the code if one parameter is unknown. Because of multiple possible answers and because of the complexity of the formula, I cannot run this script and get solutions. Any ideas how I can this calculation lighter so it is able to run? Values should be real and positive (so 1 or 2 solutions are the only one I'm interested in)

Any ideas, how I can make this code runnable? (file is below)

I'm stuck on this for a while now :/ So I hope someone will be able to help me

Many thanks in advance!l

Question.mw

Figure 1: [URL=http://s1240.photobucket.com/user/laggstar/media/Parameter%20f%20known.png.html][IMG]http://i1240.photobucket.com/albums/gg494/laggstar/Parameter%20f%20known.png[/IMG][/URL]

Figure 2: [URL=http://s1240.photobucket.com/user/laggstar/media/Parameter%20f%20unknown.png.html][IMG]http://i1240.photobucket.com/albums/gg494/laggstar/Parameter%20f%20unknown.png[/IMG][/URL]

Good afternoon.

I request your valuable suggestion for the above cited subject.

I here by uploading the file for your kind notice.

Hey,

I've been trying to divide an equation into matrixes, with not a lot of luck.

Simple example:

A=2b remade into [A]=[2]*[b]

This is a basic overview of the problem, i need it to work with bigger matrixes.

Thank you in advance.

Hi,

Following situation: I have Records with several members. These members in turn have varied expressions assigned to them: some have numbers, one has a Matrix, some have formulae. Example:

q:=Record(l=len,k1=kl/len,R=(a 6x6 Matrix dependent on len and kl/len));

I want to be able to use the limit command on each of the members of q such that each member gets assigned the correct limit of its expression. I.e. I want to write a function limit2 such that

limit2(q,len=0);

yields

Record(l=0,k1=infinity,R=(limit~(the Matrix,len=0))

The trick here is that the members of the Record vary for different Records but I want to write a function limit2 that works for all of these. I can make a list of the members by using exports(q) like this:

exlist:=[exports(q)];

and after some fiddling I found that I can run limit on each member in turn:

for nam in exlist do
  limit~(eval(parse(cat(elm,":-",eval(nam)))),len=0)
end do;

What I have not been able to do is putting the result back into the member of the Record. Usually I would use assign for such a task, but I am unable to get the correct name on the left side that lets me assign to it. These names would of course be q:-l, q:-k1 and q:-R in the above example. I tried the parse(cat(...)) construct above and variations, but in the best case the assignment does not happen, in worse cases I get an error thrown. Never do I get the actual assignment.

Any hint how to do this?

TIA,

M.D.

PS: FWIW, I am doing this on Mape 15.

I am solving a system of ODEs with dsolve(ODES, numeric, method = lsode[adamsfull]) and I noticed that some of the solutions are really small numbers, of the order of 10^-{10} and smaller. Certainly for all intents and purposes I will treat those as zero, but my question is: what flag do I set in dsolve to force Maple stop seeking for a solution when it is so close to zero and set it to 0.0? It seems like a great waste of computational time to try and find the significant digits of the order one number in front of 10^{-10} for any particular solution, at least in my case. So, is there a way to add some option in dsolve such that maple sets that to zero before trying to fully calculate it fully (i.e. all the significant digits) ?? I have looked at abserr and relerr but that does not do the trick. 

IF the question was asked before, forgive me. I have tryed to find an answer within the search here and on the maple help page but was unsuccessful. 

This should be trivial but I am not able to figure out the right syntax to execute it

The pdf is given by :

f_X(x)={ 1/25 *x, 0<=x<5

             2/5 -x/25, 5<=x<10

             0, otherwise

I have tried to use the "CumulativeDistributiveFunction" so far