Maple 2019 Questions and Posts

These are Posts and Questions associated with the product, Maple 2019

Calculation of these integrals takes much time.

Is there a way to reduce the time?

MY_SYSTEM.mw

 

I have this procedure to perform a Boole-Mobius Transform. I took me quite a while to figure out. Whereas it works, I wonder how it should be done efficiently? The document is also attached which shows the steps I went through to derive the procedure. I can't get the document to display.

BooleMobiusTransform := proc(V) 
local n, im, istep, jm, h, istart, i, j, k; n := ilog2(numelems(V)); im := 2^n/2; istep := im; jm := 1; h := 2^n; 
for k to n do
 istart := 1; 
for j to jm do 
for i from istart to im - 1 + istart do 
V(istep + i) := (V[istep + i] + V[i]) mod 2;
 end do;
 istart := istart + h; 
end do;
 im := 1/2*im; istep := 1/2*istep; jm := 2*jm; h := 1/2*h; 
end do; 
return V; 
end proc

Boole-Mobius_Transform.mw

DEAR SIR,

 

GOOD EVENING.

 

HOW TO FIND THE AREA BETWEEN THE CURVES  USING MAPLE? 

How I can edit and apply the following conditions to my plot functions 

`######   I want to change q  (starting from 0.3) from 0.3 by .001 to 0.377 and plot 2D (u-q) ,(v,q), (u,v) and  plot3D (u,v,q)`

 

`######   I want to change q (starting from 0.37727) from 0.37727 by .001 to 0.390059 and h from 0.1 by .001 to 0.138462  and plot 2D (h-q)  and  plot3D (u,h,q),(v,h,q)`

I couldn't attach my file here, so I uploaded that here

https://drive.google.com/file/d/17purRxEdDqrTJeFDcF1-d9J7b3LkuJnF/view?usp=sharing

 

Hi,

I am studying nonlinear differential equations, and came across an interesting one on maple's help page.  I made a post about this equation already, but I have decided to make a new post because the topic is slightly different than from the previous post.

The topic of this post is:

"Can numerical methods and exact, implicit techniques find false solutions?"

To make the discussion clearer, the rest of this post can be found in the maple file I created.

Hi to all community. I am trying to integrate a lengthy-expression but could not get the result after waiting of 1 and 2 hours even. is there any way to control such integration


 

Integration_Help.mw

 

 

A very simple question (by example):

Consider two polynomials g and h:

with(PolynomialTools):

g:=FromCoefficientList([1,2,3],x);

h:=FromCoefficientList([4,5,6,7],x);

 

What is the syntax for computing the composition of g with h? (As a polynomial.)

For instance, I would like to use CoefficientList on the result.

 

I know the @ operator and the subs command and have tried using them in various ways, but with no success.

(Of course, my question is general; the above is just an example.)

---

Edit: Additional question (which is my real question):

I'm writing a procedure that takes two polynomials g and h, and in which I define an unknown polynomial f. I want to compute its coefficients so that

f "composition" g = h

I write:

fCoeff:=seq(a[i],i=0..t) (to define the unknown coefficients. I can compute t.)

f := FromCoefficientList([fCoeff],x);

Then I would like to do something like:

comCoeff:=CoefficientList(f "composition" g,x)

If I have this, then I know how to solve for the unkown coefficients in f.

Given a metric, to compute quantities in the NP formalism one needs to specify a null tetrad. In the various examples in the help pages, sometimes the tetrad is specified simply as a list of 4 vectors, e.g., NT := [...] and sometimes evalDG is applied as in NT := evalDG({...]). Using the first format, Maple accepted NT as argument in NPSpinCoefficients but  NPCurvatureScalars(SpinCoefficients,NT) complained that the second argument wasn't a list of four vectors. When I used the second format, both commands returned the expected results. Why the difference?

RobinsonTrautmanSpinDG.mw

How I can plot3d function s. in the domain x ,y from -1300 to 200.

Thanks

if.mw
 

"restart;   #`    x__A`=-1300..200,      `y__A`=-1300..200    u1:=(((`x__A`-200)^(2)+(`y__A`^())^(2))*0.001)/(960000);   if  u1<=0.001  then w(u1):=-0.5772-ln(u1);  else if u1>0.001  then w(u1):=-0.5772-ln(u1)+u1-((u1)^(2))/(2*2!)+((u1)^(3))/(3*3!)-((u1)^(4))/(4*4!)+((u1)^(5))/(5*5!)-((u1)^(6))/(6*6!)+((u1)^(7))/(7*7!)-((u1)^(8))/(8*8!)+((u1)^(9))/(9*9!)-((u1)^(10))/(10*10!)+((u1)^(11))/(11*11!)-((u1)^(12))/(12*12!);     end if"

Error, invalid 'if' statement

"restart;      u1:=(((`x__A`-200)^2+(`y__A`)^2)*0.001)/960000;   if u1<=0.001  then w:=(u1)->-0.5772-ln(u1);  elseif u1>0.001  then w(u1):=-0.5772-ln(u1)+u1-((u1)^2)/(2*2!)+((u1)^3)/(3*3!)-((u1)^4)/(4*4!)+((u1)^5)/(5*5!)-((u1)^6)/(6*6!)+((u1)^7)/(7*7!)-((u1)^8)/(8*8!)+((u1)^9)/(9*9!)-((u1)^10)/(10*10!)+((u1)^11)/(11*11!)-((u1)^12)/(12*12!);     end if"

 

s := 6.87*10^(-3)*w(u1); plot3d(s, x__A = -1300 .. 200, y__A = -1300 .. 200)


 

Download if.mw

 

Hello. I want to use the command verify but with two variables. For example:

verify(x^2 + y^2, 0, {'greater_equal'});

but I get FAIL as an answer. I tried adding before the verify command assume(x, 'real'); assume(y, 'real');

but notihng changed.

 

Thanks for any help.

Dear people in mapleprims,

I haven't used maple for a long time.
By the way, I tried to modify a denominator part in an fractional expression, but I couldn't.

Original expression is 

a:=-(I__22-X__2)/(I__11*I__22-I__11*X__2-I__12*I__21-I__22*X__1+X__1*X__2);

#And, I want to change this to the form

b:=(X__2-I__22)/((x__1-I__11)*(X__2-I__22)-I__12*I__21);

How can I do this?

Thank you in advance.

taro yamada

 

Hi,

I have managed to create the following plot.  It won't plot on the site's plotter:

fieldplot([1, y^2 + x], x = -10 .. 10, y = -6 .. 6, fieldstrength = fixed, color = abs(y^2 + x + 1))

I am trying to assign a colour gradient to the different vectors based on vector magnitude.  In the color option, I entered color= expresssion for the magnitude of the vectors

 

This only half worked.  It currently scales the colours such that the largest and smallest vectors are the same colour.  How do I assign a gradient such that the small magnitude vectors are one colour, and they then transition to another colour as their magnitude gets larger?

 

 

Hello. I am trying to solve this system of equations but I can't get Maple to show all solutions.

I have solve the system by hand and there are two more solutions (x=x, y=1) and (x=x, y=-1).

 

Thanks for any help !

 

Hello. I want to solve a 2X2 system using Maple. I have written this code but I do not get expected results.

restart;
with(DEtools);
with(plottools);
with(plots);
with(Algebraic);

F := -1 - y - exp(x);
G := x^2 + y*(exp(x) - 1);

sol1 := eliminate({F, G}, {x, y});

sol1 := [{x = RootOf(-exp(_Z)^2 + _Z^2 + 1), y = -exp(RootOf(-exp(_Z)^2 + _Z^2 + 1)) - 1}, {}]

But, the solutions are x=0 and y=-2 (I have solved the system by hand).

 

Any help?!

I have a parametric polynomial which is defined based on the multiplication of different variables and I want to rearrange the polynomial based on specific variables. For example, suppose the polynomial is defined as follows:

a:= (1+x+y)(2x-yx+z)(y^2-zy)

and I want to have a based on first, and second orders of x, or even other variables. Thanks

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