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These are questions asked by Markus0805


I want to create a plot of a gradient field of a function with singularities I want to draw arrows only where the function has values below 3,   or written: where f(x,y) < 3.


potfeld := f(x, y) -> 1/sqrt(y^2+x^2);
   for i to 5 do
           for j to 3 do
                    if sqrt(i^2+j^2) <> 0 and sqrt((i-2)^2+j^2) <> 0 and potfeld(i, j) < 3
                       then P[i, j] := arrow(`<,>`(i, j), `<,>`((D[1](potfeld))(i, j), (D[2](potfeld))(i, j)))
                       else P[i, j] := arrow(`<,>`(i, j), `<,>`(.1, .1))
                   end if
           end do
    end do;
Pseq := seq(seq([P[k, l]], k = 1 .. 5), l = 1 .. 3);
display(Pseq, view = [1 .. 5, 1 .. 3], scaling = constrained);


Error, cannot determine if this expression is true or false:  (1/2)*2^(1/2) < 3.0

The "(1/2)*2^(1/2)" are the value of the function potfeld(x,y) evaluated at (1,1).

I ask for your help, as with many changes and variations I have not managed to solve this issue.
+Thx and regards+

Hello all,

I would like to carry a copy of a 3dplot to my lectures to display them there, and also rotate them in real time in front of the students.

The computer in use there does not have Maple installed on it. I only could carry such a copy of a 3dplot on a USB stick there.

Is that possible?

Best regards and thank you in advance,


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