Passing Functions to a Matrix ...

In Maple 18, I'm trying to define a matrix consisting of the output of the diff function from Physics, but it seems to return an empty matrix for some reason.

First, the setup:

with(Physics);
(D(x))(t) := x(t)^2+y(t)^2;
(D(y))(t) := x(t)^2-y(t)^2;

Then if I try to input the output of e.g. diff(x'(t),x(t)) directly into a matrix structure, it outputs an empty space for that entry.

I can work around it setting the output of diff into variables first, and then using those in my matrix structure, but that's a bit annoying.

See attached image for input/output

Strange error in diff...

Hi,

This is my first post here, so I apologize for any errors or breaking of posting etiquette. I encountered a strange problem suddenly tonight when I tried running a Maple worksheet I've run succesfully (several times, without changes) in the past. The problem occured on both Maple 18 and Maple 2015, unfortunately I haven't been able to recreate a minimal working example with the same error, since my other worksheets doesn't show the error even though they contain identical caluclations. The problem also persists between copies of the worksheet.

The error I'm recieving is
"Error, (in TypeTools/ac_var_local) unable to handle expressions as (((D@@2)(phi))(theta(t)))(t)"

It occurs whenever I try to differentiate some (not all) expressions containing the above variable. I have no idea what this error even means, and I can't find anything googling. As said previously, I haven't been able to produce the error so I can't really give a concise short example but the flow is as follows:

g0 := simplify(subs(diff(y(t), t, t) = F+N*v(t), lhs(aby)-lhs(aby_y)), 'size');
->Produces an expression containing (((D@@2)(phi))(theta(t)))(t)
diff(g0,t)
-> Gives Error

U := lhs(Vector([1, 0]).subs(subsVhcError, eom));
->Produces an expression containing (((D@@2)(phi))(theta(t)))(t)
diff(U,t)
-> Does not give error

Sorry that I can't be more descriptive, does anyone know have to sort this out, or might give me some more info on what the Error message might mean and how TypeTools are involved? As stated previously, the error just occured today and only affects one worksheet.

Edit: Link to worksheet with error
transverse_linearization.mw

Problem with dsolve...

hi.please see attached file and help me

"initial Newton iteration is not converging" in dsolve cople equations

thaks..FEREKANS2.mw

Simplify to a specific form...

The two forms below (eqn1 and eqn2) give the same result. You can convert from eqn1 to eqn2 using the expand option but is there a way can you get Maple to simplify eqn2 back to eqn1?

( I have tried all the simplify options I know)

eqn1:=

eqn2:=

Thanks.

Equation with unknown in sum...

I'm begginer and I don't know, whether this equation can be solved in Maple:

The only variable is N.

i=1,2,3,...,n

n=the nearest smaller natural number from the second expression.

The equation sides probably won't be equal precisely, also I'm looking for some N when equation side's values are close enough.

Can you help me with programming this into Maple?

 (1)

 (2)

How to solve that recursion?...

Given the sequence defined by the recursive relation a[n+1] = r*a[n](1-a[n])
You need to use the procedure iterate.
Throughout this problem you should choose initial values in the interval 0<a0<1.
(a) Let r=3/2. Calculate a moderate number of terms in the sequence (between 10 and 20). Does the sequence appear to be converging? If so to what value? Does the limit depend upon your choice of initial value? Plot the terms you have calculated
(b) Let r=2.8. Calculate a moderate number of terms in the sequence (between 10 and 20). Does the sequence appear to be converging? If so to what value? Does the limit
depend upon your choice of initial value? Plot the terms you have calculated How does this sequence differ from that in part (a).
(c) Let r=3.2. Calculate a moderate number of terms in the sequence (between 10 and 20). Show that the sequence does not appear to converging. Plot the terms you have calculated and describe how the sequence behaves in this case.
(d) Consider intermediate values between 2.8 and 3.2 to determine more precisely where the transition in behaviour takes place. Provide a few plots (no more than 4) showing the values you have investigated.
(e) Consider the values of r in the range 3.43<r<3.46. Determine as accurately as you can the value of r for which the period of oscillation doubles.
(f) As r increase further period doubling occurs. Try to find the when the sequence appears to oscillate between 8 values.
(g) Let r =3.65 and calculate a considerable number of terms (at least a few hundred) and plot your values.
(h) For r=3.65 choose a0=0.3 and then a0=0.301. Find and plot some terms in the sequence for each initial value. Determine how long the terms in the two sequences remain close together and when they begin to depart significantly from each other.

Error that I can't solve...

Hello,

In this procedure I get the error,

Error, `:=` unexpected

I know what it means I just can't seem to resolve it. Any help would be greatly appreciated! Thank you in advance for looking at this code!

Kind regards,

Gambia Man

 >

Some legitimate users erased...

There are no users with 0 reputation.  It appears all users with 0 reputation and negative reputation have been erased.  One user I can not find who is or now was a legitimate user is John Mcloone an employee at Mathematica who made a post here.  I can only think during the recent spam attack that all users with 0 or negative reputation were removed.  Some of those users had legitimate questions.  Where did those users, John Mcloone and their posts go?

Warning when solving equation...

Hi all,

I tried to find the real solution of the unlinear integral equation:

exp(-h^2/T)*(Int(exp(-x^2/T)*BesselI(0, h*x/T)*x, x = 0 .. 1))/T

but I got the warning and an complex solution:

solve(subs(T = 1, eq)-.99 = 0, h)

Warning, solutions may have been lost

-1.232350242*10^(-32)-1.130417828*I

Can anyone help me to find a real solution for this issue (if possible)...?

I would like to thank you in advance.

How to define Lie algebra?...

Hi. I have a commutation table, that I've got as output of Greg Reid algorithm.

Can I use to define Lie algebra for components DifferentialGeometry & Lie Algebras?

Worksheet is attached...

FCT.mw

In the following problem though b and c are same (except the way denominator 2 is hanfled), command ' a-b ' readily answers zero, but a-c not so. Why? Only on condition of assumption real it gives zero!

 (1)

 (2)

 (3)

Why the answer is not given as zero?

What difference therms b and c make for Maple? Are they not same?

Ramakrishnan V

rukmini_ramki@hotmail.com

Physics package archive...

On the Physics Research and development page there are only 3 versions of the Physics package available.  What happened to the earlier final updates for Maple 16, 15 etc...

What is the latest one that can work on Maple12?  Was there one for M12?  What is the earliest versions of Maple the Research & Development Physics packages can work on?

Why different plots?...

are these quations in wave form for harmonic ocillator?

i can not plot them

plot(exp(I*2*t) - exp(-I*2*t), t=0..10);

plot(cos(t) - I*sin(t), t=0..10);

why same solution but their plot graph are different?

plot(cos(t) + sin(t), t=0..10);
complexplot(exp(I*t), t=0..10);