Robert Israel

6577 Reputation

21 Badges

18 years, 217 days
University of British Columbia
Associate Professor Emeritus
North York, Ontario, Canada

MaplePrimes Activity


These are replies submitted by Robert Israel

Yes, but the Title and Alternate text are

LineInt\left( VectorField\left( \left< \frac{e^x \cos(y)-1}{e^{2x}-2 e^x\cos(y)+1}, \frac{e^x\sin(y)}{e^{2 x}-2 e^x\cos(y)+1} \right>\right), \, Circle(<0,0>,1)\right)

which is TeX, not Maple.

The problem with Maple 7 on Vista would be with the Maple executable, not with the worksheets themselves.  In general Maple 12 should have no problem with Maple 7 worksheets and .mpl files.  There have been some changes in Maple since Maple 7, so not everything will work the way it used to, but Maple tries to ensure backward compatibility, so this should be quite rare.  Due to changes in the user interface, plots in Maple 7 worksheets might not look the same in Maple 12, but if you re-execute the worksheet they should be OK.

As usual, 1D format works better than 2D.  But I don't understand how you're getting ""Teal"" unless the outer quotes were there already before you pasted it in.  Also, instead of double-clicking, you should be able to highlight just the part you want by a single click and drag.  It does require a bit more hand-eye coordination though.

Maybe, but these interruption opportunities may be few and far between, as I've had many frustrating experiences with the Stop button. 

Try this, for example (a rather difficult knapsack problem):

>   with(Optimization):
    c := [seq(rand(), i=1..100)]:
    v:= add(c[j],j=combinat[randcomb]([$1..100],50)):
    Maximize(x[1],{add(c[j]*x[j], j=1..100)=v}, assume=binary);

Let it go for, say, 10 seconds, then press the Stop button.  How long does it take before you get "Warning, computation interrupted"?

 

The plot3d command won't work with a geom3d object.  You have to use draw.

 

The "height from d" is the distance from d to the plane through a,b, and c.  So

> plane(P,[a,b,c]);
   distance(P,d);

 

Here's how I'd get a spinning torus.

> with(plots): with(plottools):
   P1:= rotate(torus([0,0,0],style=patchnogrid),Pi/2,0,0):
   f:= t -> display(rotate(P1,0,0,t)):
   animate(f, [t], t=0..2*Pi, axes=none,scaling=constrained,
      orientation=[-90,90],paraminfo=false, glossiness=1/2,
      lightmodel=light2);

The plot3d command won't work with a geom3d object.  You have to use draw.

 

The "height from d" is the distance from d to the plane through a,b, and c.  So

> plane(P,[a,b,c]);
   distance(P,d);

 

Here's how I'd get a spinning torus.

> with(plots): with(plottools):
   P1:= rotate(torus([0,0,0],style=patchnogrid),Pi/2,0,0):
   f:= t -> display(rotate(P1,0,0,t)):
   animate(f, [t], t=0..2*Pi, axes=none,scaling=constrained,
      orientation=[-90,90],paraminfo=false, glossiness=1/2,
      lightmodel=light2);

It would have been nice if the developers of existing packages which use external code (e.g. LinearAlgebra and Optimization) had made use of this mechanism.  Perhaps they could be encouraged to put it in...

That's the question I thought I answered. 

If you want the Arrays as they are, in a form that can be read by Maple, then
you can try

> save P, P1, P2, P3, "c:/mypath/myfile.txt";

If that's not what you want, maybe you can tell us in more detail what you want this file to look like.

That's the question I thought I answered. 

If you want the Arrays as they are, in a form that can be read by Maple, then
you can try

> save P, P1, P2, P3, "c:/mypath/myfile.txt";

If that's not what you want, maybe you can tell us in more detail what you want this file to look like.

This tetrahedron is not regular.  You might try gtetrahedron instead.

This tetrahedron is not regular.  You might try gtetrahedron instead.

Filtered HTML.

In Maple, highlight the output you want to include, copy it to the clipboard with Ctrl-C.

Click on the red maple leaf icon in the tool bar of this editor.  You should get a "Maple Tag" popup window.  Click on the white text area below "Maple Math Expression", and press Ctrl-V.  This should paste Maple code for your output.  Click OK.  You should see that Maple code in the editor window.  Click "Preview comment" and you should see your posting with the Maple output, e.g.

exp(x)+1/x

Note that not all Maple output will work, e.g. for a sequence such as  1,2,3 I get only the first item in the sequence:

1, 2, 3

 Also, sometimes the system seems to stop working for days at a time.

First get the list of base points, e.g.

> basepts := [seq(seq(seq( 2*[x,y,z], x = -2 .. 2), y = -2 .. 2), z = -2 .. 2)]:

Now write a function that takes a base point and returns the corresponding arrow.
 

> makearrow:= P -> plottools:-arrow(P, <0.4*P[1], 0.4*P[2], 1>, 
   .2, .4, .3, cylindrical_arrow, fringe=black) ; 

Apply this to each base point, and display the result.

> plots[display](map(makearrow, basepts), scaling=constrained, 
     axes=box);

 

First get the list of base points, e.g.

> basepts := [seq(seq(seq( 2*[x,y,z], x = -2 .. 2), y = -2 .. 2), z = -2 .. 2)]:

Now write a function that takes a base point and returns the corresponding arrow.
 

> makearrow:= P -> plottools:-arrow(P, <0.4*P[1], 0.4*P[2], 1>, 
   .2, .4, .3, cylindrical_arrow, fringe=black) ; 

Apply this to each base point, and display the result.

> plots[display](map(makearrow, basepts), scaling=constrained, 
     axes=box);

 

Oops, that was the identity that comes out of of the integral of sqrt(1+x^(-2/3)).
This one will be a bit different, but I think the same principles should apply.

> J := int(1/3*(9+2^(2/3)/x^(2/3))^(1/2),x = 0 .. U) assuming U > 0;

>  factor(27*J + 2);

(9*U^(2/3)+2^(2/3))^(3/2)

> convert(eval(%, U = t^(-1/2)), FormalPowerSeries, t);

Sum(-27*(-1)^k*pochhammer(-1/6,k)*pochhammer(1/6,k)/k!/(3*k)!*(2*k)!/(2*k-1)*27^(-k)*t^(k-1/2),k = 0 .. infinity)+Sum(9/2*2^(2/3)*(-1)^k*pochhammer(-1/6,k)*(2*k)!*pochhammer(1/6,k)*27^(-k)/k!/(3*k+1)!*t^(-1/6+k),k = 0 .. infinity)+Sum(1/2*2^(1/3)*(-1)^k*pochhammer(1/6,k)*pochhammer(5/6,k)*(2*k)!*27^(-k)/k!/(3*k+2)!*t^(1/6+k),k = 0 .. infinity)

> map(convert, %, hypergeom);

27/t^(1/2)*hypergeom([-1/2, -1/6, 1/6],[1/3, 2/3],-4/729*t)+9/2*2^(2/3)/t^(1/6)*hypergeom([-1/6, 1/6, 1/2],[2/3, 4/3],-4/729*t)+1/4*2^(1/3)*t^(1/6)*hypergeom([1/6, 1/2, 5/6],[4/3, 5/3],-4/729*t)

> simplify(eval(J, U = 2) = eval((%-2)/27, t = 1/4));

-2/27+20/27*10^(1/2) = 253/108*hypergeom([-1/2, -1/6, 1/6],[4/3, 5/3],-1/729)-911/6298560*hypergeom([1/2, 5/6, 7/6],[7/3, 8/3],-1/729)+73/9795520512*hypergeom([3/2, 11/6, 13/6],[10/3, 11/3],-1/729)-2/27

 

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