i want to have plot int.  but i get error 

"Error, (in type/EvalfableProp) too many levels of recursion"

how can i draw this plot

please help me . thank you

Simple issue. I think it is a bug, but if not, it tends to cause logic problems with new users of Maple.

with(plots):
z := A*x*y:
A:=1.0:
plot3d(z, x=0..1, y=0..1); # works as expected
contourplot(z, x=0..1, y=0..1); # works
fieldplot(z, x=0..1, y=0..1); 
    --> Error, (in plots/fieldplo) invaled 1st argument (the function) 1.0*x*y

Is there something special about what the fieldplot expects for the function? I don't see it in the help. Or is this a bug?  

Yes, there is a work around, define all constants first

A:=1.0:   z := A*x*y: fieldplot(z, x=0..1, y=0..1); 

But I fail to understand why my example should fail. (Note, I have seen this situation for every version, so it is not new.)

Silly, but what command will move the one first under the sqrt here...

a:=sqrt(1+x^2)  # maple moves the x^2 in front
                           sqrt(x^2+1)

What maple command will move the 1 in front of the x^2 under the square root?

I'm trying to plot contours in Maple, but the 2d contour plot output is not pretty. I tried the following command:

contourplot(-(1/2)*y^2-(1/2)*x^2-(1-.3)/sqrt((x+.3)^2+y^2)+((-1)*.3)/sqrt((x-1+.3)^2+y^2), x = -1.5 .. 1.5, y = -1.5 .. 1.5, axes = boxed)

and the plot is so much uglier than the 3d one:

contourplot3d(-(1/2)*y^2-(1/2)*x^2-(1-.3)/sqrt((x+.3)^2+y^2)+((-1)*.3)/sqrt((x-1+.3)^2+y^2), x = -1.5 .. 1.5, y = -1.5 .. 1.5, view = -2 .. -1.3, axes = boxed)

Is there any way I can get the same detail in the 2d one as there is in the 3d one.

Thanks in advance!

Hello everyone !

I have several values loaded into Maple as a matrix from a .txt file (output of my measurement).

I measured power in dependence on time.

Here is an example of my txt file in which the first column represents the time and the second column represents the force:

29.04 997.54
29.06 998.83
29.08 999.79
29.10 1000.76
29.12 1001.72
29.14 1003.01
29.16 1003.81
29.18 1004.94

From 3624 values I need to get specific amount of values, lets say 3000, while keeping the course. We could call it a dilution I guess.

Here is a simple illustration of the problem:

So I am asking you to help me find out some function to dilute measured values while keeping the curve.

I will be grateful for any advice.

Dear All

Please see my query below:

Download Summation.mw

Dear Friends, I work with physics paсkage. And I don't know how to simplify the next expression: Dgamma[mu]*a[mu]*Dgamma[nu]*a[nu]

(I want to obtain  the well-known result a² )

The command "Simplify" doesn't work in this case.

I am dealing relatively often with vector functions of a variable vector. Specifically these are (in general nonlinear) mappings from R^6 to R^6, and often I have one or more extra parameter that controls the map.

Often I'd like to get a first-order expansion of these. The general scheme I use to do that is to map mtaylor over the components of the function vector. Like so:

map(mtaylor,F(<x1...x6>),[x1...x6,p1...pn],order);# F(<...>)  is  <F1(<..>)..F6(<...>)>

This works fine until I hit a situation where the Taylor expansion for one of the parameters p does not exist. Then it bombs. Actually, I often can use assumptions on the parameters to prevent bombing; however, in that case I often get the unchanged function F returned. This is Bad as the whole thing happens in a loop with many concatenated functions F, and now expression swell makes Maple lock up.

In at least a significant subset of these functions, the series command works where taylor fails. "mseries", however, does not exist in Maple. So my question is whether someone has written an "mseries" command for Maple. I know how to do it in principle (but caution is needed to make it work as intended), however, I wonder whether either someone has done it before and might share his/her code, or whether there is a reason why "mseries" actually cannot work.

TIA,

Mac Dude

Hi,

I get an error when I try to create a modelica block including a piecewise function with one of its expressions including csgn function.

similarly when I use the piecewise And for its conditions.

are these not supported in Modelica?

There seems to be a bug in determining the folowing integral analytically:

Maple gives as a result

However, numerically integrating it

gives

In fact, integrating it from a to b,

gives

suggesting that Maple thinks the integrand is just 3/2. If one plots it, then it becomes obvious that this is not the case.

Hello,
When I try to put the Gcdex in a procedure and start maplemint, then there occurs an error.

Gcdex(x^2 - 1, x - 2, x ,'s','t') mod 3;

--> works

But:

restart;
a := proc()
    Gcdex(x^2 - 1, x - 2, x ,'s','t') mod 3;
end proc;
maplemint(a);

Then there is an error I don't understand.

Error, (in maplemint/expression) not implemented POLY

By the way I have a fundamental problem to understand, where the values s and t are saved after calling Gcdex (or Quo, Rem, etc.). Till now I thought, that variables s and t are created, but when I declare s, t at the beginning as local variables and start maplemint, then there is something like:

    These parameters have the same name as constants:
      3
    These local variables were used before they were assigned a value:
      r::name, (-x-1)::name, (x-1)::name

So the names of s and t changed, they don't assign a new value? I don't understand that.

Hi,
   I just finished a math quiz. I needed to find the length of the curve and area of the function, r=3*cos(theta)-2*sin(theta) bounded between 0<=Pi<=2*Pi.
   On the quiz I used Area=int(1/2*(r^2)) dtheta. For the length of the curve I used L=int(sqrt(r^2 + r'(theta)) dtheta.

How do you plug this into Maple and get an answer?
I came up with 20.42.... sq units for the area and 22.65.... for the length of the curve.

Thank you,
Jay.

Hi,

I was wondering why when I want to equate



Maple returns

I know that the maple arctan(x,y) (or atan2) plots from Pi/..-Pi/2, but at x = 0, depending on the sign of y, it should either return Pi/2 or -Pi/2. but the equation returned wouldnt do that, It will plot only from Pi/2 to 0. see below.



first, why does maple evaluate it to that particular expression of csgn?
second, how to get a "correct" result?

I cant understend how to use new Maple workbook, and i cant load it on a site so i will use screenshoots to explain. I whant to add my costume functions to code attachments and exceuted them in multitipe workshellds, but i dont know how to excecude them from ther + i cant understend how varibles sistem work. For excemple i go main document ex1, in it i save z as global varible for all worksheed, when i excecute it works alright in other workdoxument c2 but when i change it in main document it didnt change in others, but in saved varibles in ex1 saved new value of z , and in all others z is left same as it was. In such whay i can save function f2 wich is declorated in workdocument c2 as varible, it will exceute in main ex1 but any changes of f2 in c2 wudent be applied in ex2, if i declorated and excecude f1 in c1 code attachment it dont even generate in varibles tables + i dont see any whay to excecute it from ex1, so here the qestion how to excecute functions saved in code attachments in other book's wordsheets and how make saved varibles usable in all book?

Hello! I am facing the problem to making the grahp of system of ODEs in the attached file from eta=-1..1. Please see the attachment and fixed it. I will be waiting your positive response.

new_graph_exact.mw

With my best regards and sincerely.

Muhammad Usman

School of Mathematical Sciences 
Peking University, Beijing, China

Email: muhammadusman@pku.edu.cn

Mob #: 0086-13001903838