## 787 Reputation

9 years, 140 days

## MaplePrimes Activity

### These are questions asked by sand15

Maple 2018

Hi,
I had written some help pages in Maple 18 that I just migrate in Maple 2018.
This seems correct except one single point: when I try ot access them from the help menu, their names are preceeded by a  "WS" label and, when I click on it, the help page appears in a new window of my Maple's session, not in the help window.
I guess "WS" means "WorkSheet" ?
How can I force the halp page of "my" function to appear in the main help page window?

(hope I was clear enough)

## What does VectorCalculus:-Curvature repr...

Maple 2018

Hi,

I'm surprised by the result of the procedure VectorCalculus:-Curvature which is always a positive scalar quantity:
For instance
c := VectorCalculus:-Curvature(<x, sin(x)>, x):
plot(c, x=0..2*Pi)
# c >=0 for all x in [0, 2*Pi]

In the help pages it's written that the (signed) curvature for a function y(x) is y''/(1+y' 2)(3/2).

y := sin(x):
c := diff(y, x\$2) / (1+diff(y,x)^2)^(3/2):
plot(c,  x=0..2*Pi)
# c < 0 if x in (0, Pi)  and  c > 0 if x in (Pi, 2*Pi)

## How does Maple draw filled polygons?...

Maple

Hi,

Does anyone know how the command PLOT(POLYGONS(...)) fills  polygons?
I'm interested in polygons that are not simple, that is polygons for which 2 different sides without common vertex do not intersect.

## How to change the permisisons of a file?...

Maple

Hi,

Is it possible to change programmatically the permissions of a file without using ssystem?
Such as in ssystem("chmod +x MyFile") for instance

TIA

## Statistical distributions accept non int...

Maple 2018

Hi,

In statistics a  "degree of freedom" is a strictly positive integer.

The three distributions ChiSquare, StudentT and FRatio from package Statistics have degrees of freedom as parameters. Nevertheless they accept any strictly positive real values for them.
(one can verify that their "Conditions" attribute is of the form [0 < n] instead of [n::posint]).

I think this ought to be corrected in future versions

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