Dear Maple users

I have encountered a very strange error at one of my students. When using functions from the Expression Palette, she receives an error. It happens every time she is using this Palette. A reinstallation of Maple didn't help solve this issue. When using Command Completion for the very same function (for example cosine or square root), it works properly. 

She did send a Maple file to me in order for me to investigate it. I opened it and reexecuted the entire document. The error messages remained. I tried applying the functions from the Expression Palette myself resulting in the same errors. I even opened a new document and tried it again. Still an error. Then I closed Maple completely and opened it again. Within a new document, I applied a function from the Expression Palette. Now it worked!! I can't seem to understand  the logic behind this behavior. The file sent to me by the student obviously contain some kind of error, but why will this error spread to a new document, which I have opned on my own computer? My own computer does not have any issues with Maple. 

I have attached the Maple file with the errors and a screen shot. I hope someone can explain this strange behavior and tell me how I can help this student make Maple work again. 

Kind regards,

Erik V.

Maple file:

Error.mw

Dear Maple users

How do I turn a text into a Matrix of letters in the most convenient and effective way in Maple? Let's say the text contains N letters and the first n of these should be placed in the first row, the next n letters in the second row and so on. In my first question the text is one continous string of only letters a-z with no spaces or numbers, etc. 

My second question would be how I can do the same as above, if the text contains spaces, numbers and other special symbols, which should be ignored. 

The subject is Cryptography. I hope some can help.

Erik

Dear Maple users

I have created a simple Explore command in order to display what happens with a Planck curve when the temperature T increases - using the slider. Especially I would like to show how the maximum of the curve lies in relation to the visible spectrum from 400-700 nm, that is from 4*10^-7 to 7*10^-7. My idea was to somehow have this wavelength interval representing the visible spectrum displayed behind the Planck curve as a vertical rectangle. If it was a fixed plot, I could do it using the display command, but is it possible to add an extra plot to an Explore command?

I have uploaded the temporary Maple file and an image to show my intention (I don't expect the coloring ...)

Planck_curve.mw

Maybe someone can help?

Kind regards,

Erik V.

I stumpled upon an exercise involving calculating double points for the spacecurve for a vector function defined in the plane. It reduces to solving two equations with two variables. The command solve is usually the way to find solutions, but since the equation contain a trigonometric function, Maple gives the solutions parametrized by aritrary constants _Z and _B. It is however cumbersome to 'decipher' the possible solutions as I do in the attached Maple file.  

I wonder if Maple have a way to deliver the solutions numerically in the interval from -4 to 4? If it had been a single equation this would have been possible, I know. 

NB! I know I can use the symmetri in the current example, but I am interested in a general technique to solve these kind of equations. 

Download Solving_system_of_equations_including_trigonometric_functions.mw

Regards,

Erik

Dear people at Mapleprimes

My situation is the following: I have a number of bins (n bins), which all contain a specific number. I want to choose at random from these bins a number of times (N times), but in such a way that it is not equal likely that I choose from bin1, bin2 ...

Example: I have 5 bins: The 5 bins contains the numbers 50, 60, 70, 80, 90 respectively. The probabilities of choosing from these 5 bins should be 0.10, 0.30, 0.20, 0.25, 0.15 respectively. I make N = 100 selections. The output is expected to be a list with 100 numbers, for example: [ 50, 80, 80, 60, 60, 90, 50, ... , 70]. 

I could make it work myself by picking a random number from the uniform distribution from 0 to 1 and deciding if the a random number is between 0 and 0.10, between 0.10 and 0.40, between 0.40 and 0.60, etc. and then choosing the number in the corresponding bin ... I just wonder if Maple has an elegant way to to it? 

Regards,

Erik