## How to Plot Partial Sum Sequence...

I'm trying to find the partial sum of the function. Now I need to plot the first couple partial sums onto 1 graph.

I'm not really sure how to input the plot function. I was able to graph it by inputting each partial sum function but I would prefer an easier solution.

## How to Find Partial Sums of Airy's Function...

Hello,

I am trying to figure out how to find several parital sums of the Airy's Function on a common screen. I figured out how to do it for a the Bessel fucntion of order 1, but I am not given the series for Airy's . Can anyone help me with what I would plug in to maple for the Airy's function or how I would go about finding the parital sums it would be greatly apperciated.

Thanks,

Rob

## Bug in VectorCalculus:-int...

In Maple 16  (obviously, the result must be positive):

VectorCalculus:-int(x+y, [x, y] = Sector(Ellipse((1/4)*x^2+(1/9)*y^2-1), 0, (1/2)*Pi));

-2

Probably, this error occurs only in the latest versions, as in Maple 12 the output is correct. It would be interesting to know the reason for this behavior.

## How to find the value of this integral...

u[0](x)=(1/GAMMA(0.5))*int((x-tau)^(0.5-1)*(tau^2+(tau^(1.5))*(8/(3))-tau-(2)*tau^0.5),tau=0..x);

I want to find the value of this integral

thank you

## how to solve the error of extra unknowns found...

> with(DEtools);
> with(plots);
> a := diff(y(x), x) = e(x)^(-0.1e-1*xy^2);

> g := dfieldplot(a, y(x), x = -8 .. 8, y(x) = -8 .. 8, color = e(x)^(-0.1e-1*xy^2));
Error, (in DEtools/dfieldplot) extra unknowns found: xy

how to solve this?
>
>

## Fsolve and Isolate Missing Solutions...

To motivate some ideas in my research, I've been looking at the expected number of real roots of random polynomials (and their derivatives).  In doing so I have noticed an issue/bug with fsolve and RootFinding[Isolate].  One of the polynomials I came upon was

f(x) = -32829/50000-(9277/50000)*x-(37251/20000)*x^2-(6101/6250)*x^3-(47777/20000)*x^4+(291213/50000)*x^5.

We know that f(x) has at least 1 real root and, in fact, graphing shows that f(x) has exactly 1 real root (~1.018).  However, fsolve(f) and Isolate(f) both return no real roots.  On the other hand, Isolate(f,method=RC) correctly returns the root near 1.018.  I know that fsolve's details page says "It may not return all roots for exceptionally ill-conditioned polynomials", though this system does not seem especially ill-conditioned.  Moreover, Isolate's help page says confidently "All significant digits returned by the program are correct, and unlike purely numerical methods no roots are ever lost, although repeated roots are discarded" which is clearly not the case here.  It also seems interesting that the RealSolving package used by Isolate(f,method=RS) (default method) misses the root while the RegularChains package used by Isolate(f,method=RC) correctly finds the root.

All-in-all, I am not sure what to make of this.  Is this an issue which has been fixed in more recent incarnations of fsolve or Isolate?  Is this a persistent problem?  Is there a theoretical reason why the root is being missed, particularly for Isolate?

Any help or insight would be greatly appreciated.

## How to export an array from maple to matlab?...

Hi,

I need to transfer an array of size (M,N) from maple to matlab. But i dont know how to make it. Please help me for this. Thanx in advance.

Regards

Sunit

## problem with solving equation, I couldn't find any...

i := I;

assume(a>0);

assume(b>0);

assume(r>0);

assume(k>0);

assume(w>0);

Hz := k*(z^2-2*r*a+r^2)/((z-1)*(z^2-2*b*z+1));

Hzw := eval(Hz, z = exp(i*w)); assume(a > 0);

Habs := simplify(abs(Hzw)^2);

p1 := eval(Habs, w = Pi) = (10^((-3.3018)*(1/20)))^2;

p2 := eval(Habs, w = (1/2)*Pi) = (10^((-.1758)*(1/20)))^2;

p3 := eval(Habs, w = (1/4)*Pi) = (10^(6.425*(1/20)))^2;

p4 := eval(Habs, w = (1/8)*Pi) = (10^(54.5699*(1/20)))^2;

solve({p1, p2, p3, p4})

## How to use PlanePlot (after with(Student[LinearAlg...

Dear Maple experts,

I would like to visualize the equation -3*x+2*y+3*z=0  and (with other color) 2*y+3*z =0. I used the following commands:

with(Student[LinearAlgebra]):
infolevel[Student[LinearAlgebra]]:=1:
PlanePlot(-3*x+ 2*y + 3*z = 0, [x,y,z], normaloptions=[shape=harpoon], showbasis);

But I do not know how to show at the same time the second equation (2*y+3*z=0 ).

How should I proceed? Any hint?

Jean-Jaques

## Find extremes of numeric solution of ODE system...

Hello! How can I find extremes of numeric solution of ODE system obtained using "dsolve"? Can I use something like "extrema" function?

## Finding a term into an expression...

Dear friends:

I have a long expression having a/some RootOf(something..) inside it.

Any way to get just that "something..", i.e., the argument of RootOf() from that expression?

Thank you very much.

## Nonlinear system of 14 equations/unknowns, 9 param...

Hello,

this is the second time I'm writing.

I posted this question in June http://www.mapleprimes.com/questions/201781-System-Of-Parametric-Equations.

This time I have  a similar problem because I'm trying to find a solution for a parametric system of equations but the number of equations and parameters is much bigger and using the tips you gave me last time I couldn't reach any result.

Here is the system:

1) alpha[1]=v*a*u*b ;
2) alpha[2]=v*a*u*(1-b);
3) alpha[3]= v*z*c*(1-a) ;
4) alpha[4]=v*z*(1-a)*(1-c) ;
5) alpha[11]=1/2*v*a* u* b* (-p*u*b+p*u*b*a+b*g-g);
6) alpha[22]=1/2*v*a*u*(1-b)* (p u b-p u b a-b g-p u+p u a);
7) alpha[33] =1/2*v*c*z*(1-a)* (c* (-z*p*a+q)-q);
8) alpha[44]=1/2*v*z*((1-a)*(1-c)* (c*z*p*a-z*p*a-q*c);
9) alpha[12]=v*a*u*b*(1- b)*(-p*u+p*u*a+g) ;
10) alpha[13]=v*a*u*b*z*c*p*(1-a) ;
11) alpha[14]=a*u*b*z*(1-a)*(1-c) ;
12) alpha[23]=a*u*z*c*(1-a)*(1-b);
13) alpha[24]=v*a*u*z*p*(1-a)*(1-b)*(1-c);
14) alpha[34]= v*c*z*(1-a)*(1-c)*(-z*p*a+q);

I have 14 equations/unknowns and 8 parameters (a, b, c, u, v, z, p, q).

I would like to write this system only in terms of alphas. In order to do so, I usually try to find the value for the parameters and the substitute them into the equations (and I have already found b,c,g,q using this technique) but I couldn't manage to find all of them.

Howveer, as you suggested me, with Maple there is the command "eliminate" that implement exactly what I'm looking for but I can't make it work.

This is my code:

> sys := {alpha[1] = v*a*u*(1-b), alpha[2] = v*a*u*b, alpha[3] = v*z*c*(1-a), alpha[4] = v*z*(1-a)*(1-c), alpha[11] = (1/2)*v*a*u*(1-b)*(p*u*b-p*u*b*a-b*g-p*u+p*u*a), alpha[12] = v*a*u*b*(1-b)*(-p*u+p*u*a+g), alpha[13] =      z*c*a*u*(1-a)*(1-b), alpha[14] = v*z*a*u*p*(1-a)*(1-b)*(1-c), alpha[22] = (1/2)*v*a*u*b*(-p*u*b+p*u*b*a+b*g-g), alpha[23] = v*z*c*a*u*b*p*(1-a), alpha[24] = z*a*u*b*(1-a)*(1-c), alpha[33] = (1/2)*v*c*z*(1-a)*(c*(-z*p*a+q)-q), alpha[34] = v*c*z*(1-a)*(1-c)*(-z*p*a+q), alpha[44] = (1/2)*v*z*(1-a)*(1-c)*(c*z*p*a-z*p*a-q*c)};

> eliminate(sys, {a,b,c, p, q, u, v, z});

> simplify(%, size);

I also tries to substitute in the system the four parameters I already found but still I can't find a solution.

What am I doing wrong? Or the problem is that it is too complicated?

Elena

## Error, (in convert/matrix) expecting array, rtable...

hello, I put in the code:

> with(plots), with(ColorTools), with(LinearAlgebra), with(RandomTools), with(ExcelTools);
> A := `<|>`(`<,>`(1, 2, 0, 2, 3, 4, 3, 4, 7, 9, 5, 3, 4, 6, 7, 8, 3), `<,>`(0, 4, 7, 2, 2, 2, 4, 5, 6.5, 7, 5, 3, 2, 5, 9, 0, 1), `<,>`(1, 5, 2, 0, 4, 1, 2, 3, 4.3, 7, 8, 5, 3, 2, 9, 6, 4)); J := convert(Import("testB1.xlsx", "Cartesian", "E2:G18"), matrix);
Error, (in convert/matrix) expecting array, rtable or list
> B := matrix([[1], [.2], [.1], [.8], [.5], [.6], [.8], [.764], [.234], [0.4e-1], [.89], [.36], [.687], [.627], [.689], [.328], [.139]]); H := convert(Import("test.xlsx", "Cartesian", "D2:D18"), matrix);
Error, (in convert/matrix) expecting array, rtable or list
> C := [seq(Color([H[i, 1], 0, 0]), i = 1 .. RowDimension(A))];

And i get the error message everytime I try import m data list and I dont understand why. Any help would be appreciated. Thank you

Jennifer

## Module/Package - Why are some functions (proc) not...

I've been using a maple package (written by another author) on earlier versions of Maple.  Recently I have been trying to rewrite it so it's a bit more Maple 16+ friendly (since I've read that Maple is not forward-compatible). However, I have been experiencing similar strange behavior in both the original and my current version:

After saving the module to my personal library, I load with(MyPackage). Most functions work fine (all but a handful out of dozens).  However, some functions won't be recognized (e.g., Coproduct(...) will return itself Coproduct(...)).

HOWEVER, when I execute the code in the module in its own Maple worksheet, all functions are recognized and work perfectly.  I look at the difference in the code between the functions that work upon loading the package (using with(MyPackage) command in a separate sheet) and those that don't, and there is no difference.

I'm assuming I'll just have to cut and paste the hundreds of lines of code for my package into each sheet I'd like to use it in, since I haven't been able to find others experience this problem in the knowledge base.  I'm hoping someone will be able to help out, however.