## With Physics, Fundiff applied on Intc...

with(Physics) :
t:=Intc(Dirac(k1+k2+k3)*phi(k1)*phi(k2)*phi(k3),k1,k2,k3) ;

# how to force
Fundiff(t,phi(-k));

# to find
3*Intc(Dirac(k2+k3-k)*phi(k2)*phi(k3),k2,k3) ;

## How to create a zoomable star chart...

I am thinking about plotting a star chart of the whole sky. While it might not be difficult to get the (x,y)-coordinates of fairly good number of stars from star catalogues and to plot them accordingly in a 2d-plot, it might be more difficult to plot the stars according to their brightness. Also, I would like to plot the chart in cylindrical coordinate with astronomical coordinate axes for x and y. Moreover, only the brighter stars should be visible when the whole chart is shown, but when zooming in (while still having the axes visible) to have a closer look at some specific locations where I wand to make some square to show some fields, fainter stars should appear.

Is this possible in Maple ? I'd prefer to do a plot as I can really draw several squares where I want them which is not possible in my planetarium software.

## Opening a maple file...

Hi, there

I work with maple 13 and made a file that its contet is plotting curves and its size is

151 MB.Now when I want to open it the file cannot be opened completely only about a quarter of its contents rises.

Thanks for your help

REGARDS

Yegan

## How do I express a derivative of a function in ter...

Hello everyone!

I'm pretty new with Maple. I think I've understood the way Maple handles differentiation fairly well, but upon a specific request from my PhD tutor I have to perform a task which is giving me a hard time.

My question is: is in any way possible to express a derivative of a function or expression in terms of the function itself?
I'll try to explain myself with an example: let f(x) and f'(x) be the function and its first derivative:

Instead of expressing f'(x) in the way shown, I'd like to express it as a function of f(x), such as in the following:

I would apply the same process to the higher order derivatives, if possible.

A huge thank you to whoever will help me!

## Third Party Package...

Dear all

I want to know, how one can install third party package into Maple13, the package is "wkptest" i downloaded it from link http://cpc.cs.qub.ac.uk/summaries/ADTY. If anyone knows how to do this please help.

## Mean value theorem by maple 13...

Hi there,

I want to use maple 13 for calculating mean value theorem for differentiable function  f:=piecewise(-2≤x≤0, -x2 ,0≤x≤2,x2

on the interval [-2,2]. But an error occured, that is,"function must be continuous".Any help will be appreciated.

REGARDS

Yegan

## output plot grid resizing...

Has there been any progress with new commands for Maple 13 that allow one to auto-resize the plotting grid?

I am generating fractals with Maple 13 and resizing the plot output grid manually is not an option because it distorts it. Neither is the option to resize it once and recalculate, because the final grid contains many points.

Any pre-processing or massaging code prior to executing the main code is very welcome (if it can be done).

Many thanks,

Yiannis

## How to create a separate number-scaled color bar f...

Matlab seems to be pretty strong at doing color plots with separate color bars, e.g.

Is this also possible in Maple and somehow in combination with `plots[surfdata](...,color=zhue,...)`?

## How to adjust color hue...

In a 3d coordinate system I have a circular spacecurve with z-minimum -4 and z-maximum +4. In the same 3d coordinate system I have a 3d surface plot with z-minimum -0.5 and z-maximum +1.3 . When I choose the color option "Z(Hue)" in order to color-code the z-values on the 3d surface and make the topography more clear, I mostly get a totally green 3d surface. It seems that the color scaling is coupled with the spacecurve with z-values of +-4 . How can I uncouple the color scaling from the spacecurve and couple it with the z-range of the surface, while the color-limits shall be at +-1.3 ?

## Error, (in DEtools/convertsys) unable to convert t...

Hello i want to solve the differentiel equation but i have these problem i don't understund  why !?

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thanks for your help

## Export 3d plots as vector graphics...

It seems a frequent issue that exported 3d plots are not shown as wished. I experience the same problem. Although I exported in the .eps format into a .tex latex-file the resulting .pdf-file shows a somewhat pixelated image of my 3d plot as if it was created in "Paint". Is there a solution for this in Maple13?

## How to broaden the z(Hue) color range...

Take a 3d plot of some uneven surface in the xyz space and you want to have the surface colored according to local z-coordinates (e.g. a valley is blue, a peak is red with all rainbow colors inbetween). For such a color-coding one can in principal select the plot option "Color->Z (Hue)". What do you do if the valley and the peak are still more or less green colored? How can you force the valley and peak to have different colors?

I have this surface which I display with the following commands:

Belt:=plots[surfdata](Surface,color=C,labels=["x","y","z"]):

display({...,Belt});

It all works, and the surface has nice default rainbow colors, but when I choose Color->Z (Hue) everything turns to green. Also when I manually write in the first of the above lines "color=["Blue","Red"]" the surface turns all red. The ranges of the x and y axis are larger than the z axis by a factor of about 50. Might this be the problem? How can I adjust the color ranges for my small z axis?

## spacecurve label...

How would you insert a label-coordinate in this command:

textplot3d([subs(E[11]=0,x[11]),subs(E[11]=0,y[11]),subs(E[11]=0,z[11]),"Planet"]):

## How to fill the space between two spacecurves?...

What is the command for filling the space between two circular spacecurves? Something like a Saturnian ring?