Maple Questions and Posts

These are Posts and Questions associated with the product, Maple

See A342180 in OEIS. Two codes have been written for this, one in Python (17 terms found), the other in Mathematica (33 terms). Could a Maple code go beyond a(33), assuming higher terms exist? 

So in multivariate calculus there is a function called Lagrange Multipliers that searches for maxima, minima and saddle points on a 3d surface with an algebraic as a constraint. I was wondering if there was a way to do something similar on a polygon constraint by feeding the corner points to a procedure and returning all extrema and saddle points? Ideas I've had so far is using the directional derivative on the corners in the direction towards the next corner and looking if it is bigger or equal than 0 if multiplied with the directional derivative towards the previous corner (if yes, extrema or saddle point, if no not) however this adresses only corners and there may be extrema on the lines between the corners too. What should I do for that? 

Hi,

Is there a way to make all computations in Maple to run modulo specified prime p? If, for example, I want to use a function such as DifferentialAlgebra:-RosenfeldGroebner and force it to run its internal computations modulo p, can this be done?

So far I have tried to use GF(p, k), but there seem to be issues where `+` and other operations require defining all symbold via :-ConvertIn(). 

Thanks.

 

I was hoping to find a nice symbolic solution for the root of this equation:

a,c,d,k are parameters.
Unfortunately, I got an RootOf expression, which does not make sense to me. Assumptions do no help me further.

Next week, I have to present my results, but I don't know how to interpret is (the help file does not bring any relief). Is there something to say about the root? Suppose, I wanted to use side restriction on a problem? E.g., find a solution conditional on the fact that the derivative is zero. 


Clearly, in the plot it seems simple.

In one case there is a solution Maple provides: a  (a parameter)

This seems strange, because numerically there is one solution (and clearly not a).

restart

version(); interface(version)

 User Interface: 1502365
         Kernel: 1502365
        Library: 1502365

 

1502365

 

`Standard Worksheet Interface, Maple 2020.2, Windows 10, November 11 2020 Build ID 1502365`

(1)

f := proc (t) options operator, arrow; c/(1+exp(k*(t-a)))-c*(t-a)*k*exp(k*(t-a))/(1+exp(k*(t-a)))^2+d/(1+exp(-k*(t-a)))+d*(t-a)*k*exp(-k*(t-a))/(1+exp(-k*(t-a)))^2 end proc

proc (t) options operator, arrow; c/(1+exp(k*(t-a)))-c*(t-a)*k*exp(k*(t-a))/(1+exp(k*(t-a)))^2+d/(1+exp(-k*(t-a)))+d*(t-a)*k*exp(-k*(t-a))/(1+exp(-k*(t-a)))^2 end proc

(2)

assume(k > 0)

additionally(a > 0)

additionally(t > 0, t < 21)

about(a, k, t)

Originally a, renamed a~:
  is assumed to be: RealRange(Open(0),infinity)

Originally k, renamed k~:
  is assumed to be: RealRange(Open(0),infinity)

Originally t, renamed t~:
  is assumed to be: RealRange(Open(0),Open(21))
 

 

interface(showassumed = 0)

0

(3)

solve(f(t) = 0, t)

Warning, solve may be ignoring assumptions on the input variables.

 

(k*a+RootOf(-(exp(_Z))^4*d+(exp(_Z))^3*_Z*c-(exp(_Z))^3*_Z*d-(exp(_Z))^3*c-3*(exp(_Z))^3*d+2*c*_Z*(exp(_Z))^2-2*(exp(_Z))^2*_Z*d-3*c*(exp(_Z))^2-3*d*(exp(_Z))^2+c*_Z*exp(_Z)-d*_Z*exp(_Z)-3*c*exp(_Z)-d*exp(_Z)-c))/k

(4)

[allvalues(%)]

[(k*a+I*Pi+(2*I)*Pi*_Z1)/k, (k*a+RootOf(-d*(exp(_Z))^2+c*_Z*exp(_Z)-d*_Z*exp(_Z)-c*exp(_Z)-d*exp(_Z)-c))/k]

(5)

Re([op(%)][1])

a

(6)

Re([op(`%%`)][2])

(k*a+Re(RootOf(-d*(exp(_Z))^2+c*_Z*exp(_Z)-d*_Z*exp(_Z)-c*exp(_Z)-d*exp(_Z)-c)))/k

(7)

a := 'a'; b := 'b'; c := 'c'; d := 'd'; k := 'k'; t := 't'

a

 

b

 

c

 

d

 

t

(8)

Now, numerically:

b := 40; k := .3; a := 10; c := 2.8; d := -1.5

40

 

.3

 

10

 

2.8

 

-1.5

(9)

RealDomain:-solve(f(t) = 0, t)

11.02361521

(10)

plot(f(t), t = 0 .. 20, color = "DarkBlue", thickness = 2)

 

``


 

Download Please_NO_RootOf.mw

Let d and i two integers 

Put 

A := -(sum((-1)^k*binomial(i, k)*pochhammer(d*k+1, i), k = 0 .. i))/factorial(i)

and 

B := (sum((-1)^k*binomial(i+1, k)*pochhammer(d*k+1, i+1), k = 0 .. i+1))/(d*factorial(i+1))

Question: Show that A=B

Thanks!

I have:

dx6PN := 9836.535181*(1 - 2.890681911*x(t) + 4*Pi*x(t)^(3/2) + 3.753665653*x(t)^2 - 37.77895388*x(t)^(5/2) + (120.1000376 - (856*ln(16*x(t)))/105)*x(t)^3 + 54.24658055*x(t)^(7/2) + (9.292369248 - 23.08463043*ln(x(t)))*x(t)^4 + (540.5708789 - 102.446*ln(x(t)))*x(t)^(9/2) + (415.3887908 + 318.8547366*ln(x(t)))*x(t)^5 + (1549.709468 - 384.6723254*ln(x(t)))*x(t)^(11/2) + (2172.892557 + 407.4405529*ln(x(t)) + 33.2307*ln(x(t))^2)*x(t)^6)*x(t)^5

Ms := 0.0003214719000

xlow := 0.04672277118

tin := 4.125604512

I want to solve the following for t>tin to obtain xphi. I then want to plot xphi over the range tin to tin+1:

diff(x(t), t) = dx6PN, diff(xphi(t), t) = (x(t)^(3/2))/Ms, x(0) = xlow, xphi(tin) = 0

I could use some help.

Hi,

Is there a possibility of aligning choices in a horizontal manner?

Thanks

QuizzTest1.mw

Given two lists say of same number of elements 

 

A = [1,0,3,4,5,5]

B=[0,1,2,6,3,6]

How to write a code find number of elements of A which are greater than the number of elements of B index wise in the above 1>0,3>2,5>3 so three elements. 

And also the number of elements of B greater than the number of elements A index wise

1>0,6>4,6>4.hence 3 elements

 

Index wise compared to note 

 

Kind help 

 

Hi everybody, I want to find 

the second-order derivative according to alpha. Since the computer could not calculate in this way, I took the derivative twice in a row.

assume(alpha <= 1)

additionally(0 < alpha)

then output is

again using the fracdiff 

then output is 

but I want to see

after the last command. Should alpha be defined specifically for this?

I know that the angle between two vectors u = (2, 1, 1) and v = (9, -1, 4) equal to 30 degree. How to find the some options of two vectors u = (a, b, c) and v = (x, y, z), where a, b, c, x, y, z are six integer numbers so that  the angle between two vectors u and v equal to 30 degree?

Bagaimana cara menemukan domain f (x) = x 2 -x + 3?

Dan bagaimana saya bisa menemukan rentang y = f (x) -g (x) jika fungsinya diketahui f (x) = x 2 -x + 3 dan g (x) = 3x-5?

Given a Graph say G with its adjacency matrix say. 

Consider a edge uv in the graph say 

how to find the number of vertices of 

Case1 : The number of vertices of graph G whose distance to the vertex v is smaller than the distance to the vertex u.

Case 2:  The  number of vertices of graph G whose distance to the vertex u
is smaller than the distance to the vertex v.

To u is adjacent to V that is uv is a edge here. 

I installed Maple 2021 on windows 10. And wanted to try it to see if the hangs I used to have are fixed now.

First I noticed that Physics package does not come pre-installed with Maple 2021, which is little strange. I would have expected Maple 2021 to come with latest Physics version.

Because when I did Physics:-Version() it says "`The "Physics Updates" package is not installed`"

Then I typed  Physics:-Version(latest) to install it, it gives error

Error, (in Physics:-Version) unable to determine the Physics Updates version, could you please report the problem to support@maplesoft.com
 

 

I remember something similar in earlier version of Maple but can't find or remember where that post now.

May be Physics needs to be updated at Maple site to work with Maple 2021? I am asking, because Latex() does not work without Physics installed.

Edit:

I think in Maple 2021, latex() now is the same as the earlier Latex() command from Physics? I remember a post saying this now. Since I see now latex() have different help page from old latex() help page.

So may be that is why Latex() did not work. I can easily change this in my code to change it to use latex() instead of Latex() in this case. 

Windows 10

 

 

 

Hello!

I have a difficulty with a function used in procedure. The procedure uses a multivariable function and if the specific choice of the function is not made the procedure seems to give proper result, but In case I make a specific choice of the function and then try use this procedure gives me incorrect result.

To be more exact I use Physics package (there is a need to calcute combinations of covariant derivates ). The calculations are performed in a curved space with a defined metric.

So here is the procedure:

SD2 := proc (psi) SumOverRepeatedIndices(g_[`~kappa`, `~lambda`]*(d_[kappa](d_[lambda](psi(X)))-Christoffel[`~sigma`, kappa, lambda]*d_[sigma](psi(X))))^2-SumOverRepeatedIndices(g_[`~kappa`, `~rho`]*(d_[kappa](d_[lambda](psi(X)))-Christoffel[`~sigma`, kappa, lambda]*d_[sigma](psi(X)))*g_[`~lambda`, `~tau`]*(d_[rho](d_[tau](psi(X)))-Christoffel[`~gamma`, rho, tau]*d_[gamma](psi(X)))) end proc;

If I turn to the procedure :

SD2(psi);

the result is  correct.

But  then I specify a psi function:

psi:=(t,r,x,y,z)->chi(r)+q*t;(here q is supposed to be a constant)

and turn to the procedure once again:

SD2(psi);

It gives me a wrong result.

I don't know what is the reason.

Thank you.

 

 

 

I’ll admit it. There are times when I don't fully understand every mathematical advancement each release of Maple brings. Given the breadth of what Maple does, I guess that isn't surprising.

In development meetings, I make the pretence of keeping up by looking serious, nodding knowingly and occasionally asking to go back to the previous slide “for a minute”. I’ve been doing this since 2008 and no one’s caught on yet.

But I do understand

  • the joy on a user’s (Zoom) face when they finally solve a complex problem with a new version of Maple
  • the smiley emojis that students send us when they understand a tricky math concept with the help of an improved Maple tutor
  • and the wry smile on a developer’s face when they get to work on a project they really want to work on, and the bigger smile when that project gets positive feedback

These are all moments that give me that magic dopamine hit.

The job that Karishma and I have is to make users happy. We don’t have to be top-flight mathematicians, engineers or computer scientists to do that. We just have to know what itch to scratch.

Here’s some things I think might give you that dopamine hit when you get your hands on Maple 2021. You can also explore the new release yourself at What’s New in Maple 2021.

Worksheet mode has been my go-to interface for when I just want to get stuff done. This is mostly because worksheet mode always felt like a more structured environment for developing math when I didn’t have all the steps planned out in advance, and I found that structure helpful. I’d use Document mode when I needed to use the Context Panel for math operations and didn’t want to see the commands, or I needed to create a nice looking document without input carets. And this was fine – each mode has its own strengths and uses – but I what I really wanted was the best of both worlds in a single environment.

This year, we’ve made one change that has let me transition far more of my work into Document mode.

In Document Mode, pressing Enter in a document block (math input) now always moves the cursor to the next math input (in previous releases, the cursor may have moved to the start of the next line of text).

This means you can now quickly update parameters and see the downstream effects with just the Enter key – previously, a key benefit of worksheet mode only.

There’s another small change we’ve made - inserting new math inputs.  In previous releases of Maple, you could only insert new document blocks above the in-focus block using a menu item or a three-key shortcut.

In Maple 2021, if you move the insertion point to the left of a document block (Home position), the cursor is now bold, as illustrated here:

Now, if you press Enter, the in-focus prompt is moved down and a new empty math input is created.

Once you get used to this change, Ctrl+Shift+K seems like a distance memory!

@Scot Gould logged a request that Maple numerically solve a group of differential equations collected together in a vector. And now you can!

Before Maple 2021, this expression was unchanged after evaluation. Now, it is satisfyingly simpler.

We’ve dramatically increased the scope of the signal processing package.             

My favorite addition is the MUSIC function. With some careful tuning, you can generate a pseudo power spectrum at frequencies smaller than one sample.

First generate a noisy data set with three frequencies (two frequencies are closer than one DFT bin).

with(SignalProcessing): 
num_points:= 2^8: 
sample_rate := 100.0:
T := Vector( num_points, k -> 2 * Pi * (k-1) / sample_rate, 'datatype' = 'float[8]' ): 
noisy_signal:=Vector( num_points, k -> 5 * sin( 10.25 * T[k] ) + 3 * sin( 10.40 * T[k] ) - 7 * sin( 20.35 * T[k] )) + LinearAlgebra:-RandomVector(num_points, generator=-10..10):
dataplot(noisy_signal, size = [ 800, 400 ], style = line)

 

Now generate a standard periodogram

Periodogram( noisy_signal, samplerate = sample_rate, size = [800, 400] )

This approach can’t discriminate between the two closely spaced frequencies.

And now the MUSIC pseudo spectrum

MUSIC( noisy_signal, samplerate = sample_rate, dimension = 6, output = plot );

The Maple Quantum Chemistry Toolbox from RDMChem, a separate add-on product to Maple, is a powerful environment for the computation and visualization of the electronic structure of molecules. I don’t pretend to understand most of what it does (more knowing nods are required). But I did get a kick out of its new molecular dictionary. Did you know that caffeine binds to adenosine receptors in the central nervous system (CNS), which inhibits adenosine binding? Want to know more about the antiviral drug remdesivir? Apparently it looks like this:

We put a lot of work into resources for students and educators in this release, including incorporating study guides for Calculus, Precalculus, and Multivariate Calculus, a new student package for ODEs, and the ability to obtain step-by-step solutions to even more problems.  But my favourite thing out of all this work is the new SolvePractice command in the Grading Tools package.  Because it lets you build an application that does this:

I like this for three main reasons:

  1. It lets students practise solving equations in a way that actually helps them figure out what they’ve done wrong, saving them from a spiral of frustration and despair
  2. The same application can be shared via Maple Learn for students to use in that environment if they don’t have Maple
  3. The work we did to create that “new math entry box” can also be used to create other Maple applications with unknown numbers of inputs (see DocumentTools). I’m definitely planning on using this feature in my own applications.

Okay, yes, we know. Up until recently, our LaTeX export has been sadly lacking. It definitely got better last year, but we knew it still wasn’t good enough. This year, it’s good. It’s easy. It works.  And it’s not just me saying this. The feedback we got during the beta period on this feature was overwhelmingly positive.

That’s just the tip of the Maple 2021 iceberg of course. You can find out more at What’s New in Maple 2021.  Enjoy!

 

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