Hello there, 

Would you allow me to ask this question?

Is there any way to apply 'collect' command using a term by multiplication of variables?

The following worksheet shows an example. What I wanted to see is the 'desired' expression, while multiple attempts with 'collect' command failed. 

Download Q20220602.mw

I would like to compute the Fourier transform of a impulse train for applications in signal processing.  I expect to get an impulse train as a result, but do not:

restart;
delta__t:=t->sum(Dirac(t-k*T__0),k=-infinity..infinity) assuming T__0>0
with(inttrans):
S:=fourier(delta__t(t),t,omega)

I will note that Mathematica has the DiracComb function since 2008.  It also computes the result as an impulse

train:https://reference.wolfram.com/language/ref/DiracComb.html which is what I would expect.  Is there something I should be doing that I'm not aware of?

Why is Maple not assigning values to A and B in the below example (Maple2018)?

restart;
assume(A < B);

S := 2/(B-A);
                                  2  
                           S := -----
                                B~ - A~
B := 10; A := 5;
                            B := 10
                             A := 5
S;
                               2  
                             -----
                             B~ - A~

I have been trying to figure out if there is any command in Maple where you can find the self-intersection points of a vector valued function in Maple? Other than having to type the equations manually into fsolve?  

Like shown in this 2013 post. 

https://math.stackexchange.com/questions/243065/self-intersection-of-vector-valued-function

Hi everyone

I have a partial differential equation in function u that contains conjugate of u. How can I write PDE like this in maple

PDE:=diff(u,t)+diff(u*,x)

where u=u(x,t) is complex function and u* is conjugate.

Why is it not as simple as

to obtain a result for the cubic root of -8 that is what one would expect: -2?

Instead we obtain

Why doesn't Maple return -2?

By printing each processing step for a parametric surface entered in 3-dimensional space,

i- Finding whether the surface is a ruled(regle) surface and printing it in the ruled surface form,

ii- Calculating the dispersion parameter of the surface and the throat line,

iii- Draws the surface and the throat line on the surface together,

When I run this code, I will get a error information:

CompositionSeries(SmallGroup(336, 209))

It's mean this function just work in transitive group? But IsTransitive(SmallGroup(336, 209)) will get true. Is it a bug of maple? Or do I have any misunderstandings?

Hi,

I am using the following (dummy) code to generate a density plot.

densityplot(x-y^2, x=-5..5, y=-5..5, axes=boxed, style=patchnogrid, numpoints=1000, legendstyle=[location=bottom], labels=[x, y]);

While this command does generate x vs y plots with varying color shared, I cannot figure out where the function (x-y^2) value by looking at the color shades. Is there a way to produce a legend along with the plot that will demonstrate how the function is taking different values with parameters? 

I found a similar post, dated 2005, that suggests using the "s_tyle=" command. However, it does not work for some reasons. I would appreciate help in this regard. 

Thank you,

Omkar

I know you can filter a dataframe by putting constraints on the numeric columns. However, I would like to sort and filter based upon a given string in a column, is this possible? I cannot immediately find this in the help files. Thank you for your assistance.QuestionDataFrame.mw

Hi MaplePrimes. 

I have a cubic with some parameters that I would like to solve and recieve 3 real solutions, however I cannot seem to find a way to get that to work while using assumptions. I always recieve 1 real and two complex conjugate answers. I have tried assuming the discrimant to be greater then zero but nothing seems to be working, and I have looked through a few posts on here but I cant seem to find anything out. In particular solve({f,conditions},{variable}) 

If I solve with a known set of paramters(which i determine graphically) that gives three solutions everything works fine. Also if I solve the cubic generally and recieve the two complex solutions and one real then substitute the paramters in I get the same correct answers, so I am slightly baffled. If I have missed something simple my apologies. 

Any help would be greatly appreciated. File attached. 

CubicSolve.mw

HI, I have numerically solved the given problem using the dsolve command But I want to solve the same problem using the Differential transformation method.
Can anyone help me to get the series solution for the given problem using DTM.

I want to compare the numerical results with DTM results when lambda =0.5.

eqn1 := diff(f(eta), `$`(eta, 3))+f(eta)*(diff(f(eta), `$`(eta, 2)))-(diff(f(eta), eta))^2-lambda*(diff(f(eta), eta)) = 0.

eqn2 := diff(theta(eta), `$`(eta, 2))+f(eta)*(diff(theta(eta), eta))*Pr = 0

Bcs := (D(f))(0) = 1, f(0) = 0, (D(f))(infinity) = 0, theta(0) = 1, theta(infinity) = 0;

[lambda = .5, Pr = 6.3]

Evaluating this integral

produces an infinite product as output. Why does Maple not automatically simplify to infinity. Can the extra information (1+pi) be of any use?

Download Infinity_times_something.mw

Please how can I define two sequences in a procedure with two arguments?

  ans:= Array([seq( [j, doCalc(j, u)], j=-2..0, 0.006, u=1..334)]):

The procedure is doCalc(j,u)  and I received this error: invalid input: seq expects between 1 and 3 arguments, but received 4

Find attached my complete code.Seq_Proc.mw

Good Morning Guys,

Please, could somebody help me with my problem in Maple?

The expression y' = y^4 * cos(x) + y*tan(x) with start-value y(0) = 0.5 has the solution of 1/root(cos(x)^2 * 8*cos(x)-3 * sin(x),3).

If I try to solve it with this method dgl_2 := diff(y(x), x) = y(x)^4*cos(x) + y(x)*tan(x) I don't get the right solution. Is it possible to solve this expression with a Tutor app? step by step? If yes I would so happy to tell me how I can do that. 

Thanks a lot and I wish you all a nice sunday and stay safe.