721 Reputation

15 years, 144 days

I have a degree in Mathematics and Physics from the Danish University Aarhus, comparable to a masters degree with thesis - majoring in Mathematics. In 1991-92 I was a visting scholar at UCLA, Los Angeles, following graduate courses in Applied Mathematics. Since 1992 I have been a teacher in a high school (gymnasium) in Denmark. Special interests: Applied mathematics, graphics and popularizing Mathematics.

How to receive numerical data from a Par...

Maple

Dear Maple users

I have been investigating the one-dimensional Wave Equation for the vibrating string with fixed endpoints. Before trying to use Maple for a solution, I surfed on Google and stumbled upon a solution given in a GeoGebra animation:

https://www.geogebra.org/m/eKkFV8uz

I succeded in making a similar animation in Maple. See the attached Maple file: The last line is out-commented in order for the file not to be too big (saving many frames...). Remove the # and recalculate, select the animation object and eventually resize it. Then hit the Play Button in the Toolbar. It should work very much like the animation above.

Now my question: I assume the numerical solution is solved using the Finite Difference Scheme in the background? How do I receive the numerical data, which lies behind the animation? Is it possible to evaluate the solution at specific (x,t) points?

I am quite impressed that GeoGebra can solve this PDE, by the way!

Regards,

Erik

Wave_Equation_-_vibrating_string2.mw

Partial derivative evaluated at a point...

Dear Maple users

I have a possibly quite easy question: How do I calculate or refer to a partial derivative evaluated at some specific point? The Maple documentation was no help to me in this regard. I hope the picture below indicate what I am looking for. I am using Maple 2D notation, but not excited about using the vertical line as evaluation. What ways can it be accomplished?

Erik

Evaluating expressions inside an Explore...

Dear Maple users

Let's say I want to plot a line containing a parameter, for example (a+2)*x+6, where a is the parameter. When using the following Explore command:

Explore(plot((a+2)*x+6, x = -5 .. 5, view = -10 .. 10), parameters = [a = -4.0 .. 3], initialvalues = [a = 1])

I will be able to change the value of a by using the slider. The actual value of a is currently displayed as well. Now, However, I want to have the current value of the slope of the line displayed as I move the slider. How is this done? When using a print command inside the Explore command the value of a+2 is not displayed, rather "a+2". Can I use some kind of component?

I hope someone can help.

NB! I constructed this rather doll example, just to make it simple.

Regards, Erik

Special operators in Maple...

Maple

Below I wanted Maple to calculate the 4. degree Taylorpolynomium of a function f around x = 7. As shown below, Maple delivers a polynomial, but not a function definition. In other words one cannot have the polynomial evaluated at a specific value. The reason for this is obvious: The value 3 of x is passed to the command, implying 3 = 7 is a parameter to the command: Therefore the error message. I solved the problem by using the unapply command, but this operation is a bit tedious. I think I remember there is another more simple operator to make the same happen in Maple. I hope someone can remind me of that one!

Regards,

Erik

Using the Explore command to produce mor...

Maple 2016

Dear Maple users

I was using the animation command to create an animation consisting of a running sine curve with a ball following the curve, as shown below. I wonder if it is possible to create it with the Explore command too? Or is this command more limited? I need to be able to add more animations, like I can with the display command ...

Regards, Erik.

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