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These are questions asked by sand15

I'm presently checking the ability of inttrans:-laplace to give results one can find in the literature.
Unfortunately the inttrans:-laplace's  answers are sometimes more complex than those published in the literature and I'm not capable to simplify the output.

For instance

f := (t+1)/sqrt(t^2+2*t);
L := laplace((t+1)/sqrt(t^2+2*t), t, p);

expresses L in terms of WhittakerW and BesselK(0, p) functions as the answer simply is

exp(p)*BesselK(1, p)

How can I get this result with Maple?


How can we manage them?

During the last few days
@Madhukesh J K

have both asked a similar question on the same topic (HPM) and uploaded both quite the same code (same name of variables, same commands and same syntax errors).
This reveals an obvious close proximity of these three OP.

Given the extreme resemblance of the three threads, my guess is that there is a single person behind those three login names who expects that asking the same question from different login names will prevent the moderators from moving the new thread to an old one, and thus keeping his question in the foreground?

Am I on the wrong track (in which case I humbly ask the three OPs to excuse my words[1])
If not, how can we prevent this type of behaviour?

[1] but, as it is likely that they are then close colleagues from the same lab they should coordinate not to ask the same question three times.

Here is a notional example of a user defined  Probability Distribution:

  • One of the "attribute" or "property" (sorry but I don't know the correct word to use) in any known distribution (that is already implemented in Maple) is Parameters: an example is  provided for a Gaussian RV.
  • In a first stage I define a simple Distribution named MyDist and declare X as a random variable of distribution MyDist.
  • Then I decide to complete the definition of MyDist by adding the "property" Parameters.
    I get an error I don't know how to get rid of.

Does anyone has any idea to fix that ?

PS: I browse the Statistics library to try and understand how this "property" is defined for a known distribution but I couldn't find any clue.

Thanks in advance.



G := RandomVariable(Normal(a, b)):


Conditions, ParentName, Parameters, CharacteristicFunction, CDF, CGF, HodgesLehmann, Mean, Median, MGF, Mode, PDF, RousseeuwCrouxSn, StandardDeviation, Support, Variance, CDFNumeric, QuantileNumeric, RandomSample, RandomSampleSetup, RandomVariate, MaximumLikelihoodEstimate


[a, b]


MyDist := (mu, Sigma) -> Distribution(Mean=mu, Variance=Sigma):

X := RandomVariable(MyDist(m, V));
(Mean, Variance)(X);



m, V


MyDist := (mu, Sigma) -> Distribution(Mean=mu, Variance=Sigma, Parameters=[mu, Sigma]):

Y := RandomVariable(MyDist(m, V));

Error, (in Statistics:-Distribution) invalid input: too many and/or wrong type of arguments passed to NewDistribution; first unused argument is Parameters = [m, V]


m, V




I am a newbie in the use of the Physics package.
As I'm interested in modeling dynamic articulated systems, I began reading the example about Mechanics (Statics).

My question is quite simple: let F some vector force of components a * _i and b * _j , what does abs(F) represent? 

I naively thought that abs(F)  was the modulus of F and expected it to be non negative. But I get some negative values (as in the tutorial example for some values of angle alpha.

Thanks in advance

I inadvertently discovered that the save command (and probably read, write, export and import commands too?) returns an error (something like "can't write ...") when the file length is too large (265 in my case).

Is this documented somewhere?
Is there a way to exceed this limit?
Assuming D=".../" and F="xxx.m", can we set the path of the directory D to some value and then use save something, F instead of save something cat(D, F) ?

Thanks in advance

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