Hello,

I am a student and using Maple to type homework assignments because of the math symbols available.  I was using Maple 17 but upgraded to 18, and its not as easy to use as 17.  For right now I am using it in text mode, because that is what I need.  But I can't figure out an easy way to do subscripts and superscripts in text mode.  Also, the "element symbol," where is it?  I feel like a lot of stuff is missing.  For instance, the arrows, the sideways triangle, lots of symbols I used before the upgrade I cant find.  Can someone help please???

After using Simplify the indices are are arranged in the tensor.  I am using the April 14th update from the Physics R&D page.

Download Vacuum_Solutions_(Kerr-Schild)_3.mw

Here is a problem I have with the Nabla operator:

I am working on a demonstration involving Maxwell's equations:

restart:with(Physics[Vectors]);
Setup(mathematicalnotation = true);
# Maxwell's eqn
M4 := `&x`(Nabla, B1_(x, y, z, t)) = mu*epsilon*(diff(E1_(x, y, z, t), t));

eval(subs(B1_(x,y,z,t)=Bxx(x,y,z,t)*_i+Bzz(x,y,z,t)*_k,M4)); # transverse magnetic field, no longitudinal (j) component

# Ok, this one is as expected.

eval(subs(B1_(x,y,z,t)=Bxx(x,y,z,t)*_i+Bzz(x,y,z,t)*_k,M4)) assuming real;

# Hmm... why is this zero?

eval assuming real seems to make them all zero. In this little example, Bxx and Bzz are just arbitrary functions and therefore the result cannot be zero in general. The bother here is that I later use a parametrization of the field (the Bxx and Bzz) which in fact does make curl(B) = 0. I wanted Maple to demonstrate that the parametrization does that, but it appears i can make the result zero for any B-field, which sort-of defeats the purpose. If I don't assume real, with the other parametrization Maple isn't getting anywhere...

So, how can I get correct results while declaring variables to be real when they are... ?

Thanks,

M.D.

Maxwell_test.mw

In Physics[Vectors] the operation ChangeBasis exists to change between different coordinate systems (Carthesian, cylindrical and spherical). The cylindrical system uses the third coordinate (_k) as its axis.

As it happens, in my work the axis of the cylindrial system should be the 2nd one (_j). I do not want to reformulate everything as this would become non-standard and confusing. I am wondering whether it is conceivable to "retrofit" the Physics package to allow for that. At issue are not so much the formulae; I can do the transformation "by hand", but that is a bit clumsy and I am looking for a way to have this integrated better in the Physics package so that all other operations (e.g. Nabla) do the expected.

I have looked for and not found something like an "addBasis" command. Am I missing something obvious here? I should add that some of my work happens on Maple 15 (Mac OS X PPC so no upgrade possible); if something like this was added recently I may have missed it, although I do have access to Maple 17 as well so I could use that version for this particular problem. Is the source of Physics actually open?

TIA,

Mac Dude

Hi! 

When trying to find the fundamental solution of the Heat equation using Maple (software), I get the following Error message which seems to have no documentation available (?) :

Using :

          PDE := -(diff(f(x, t), t))+(diff(f(x, t), x, x))*Di = 0

assume(epsilon > 0);

pdsys := [PDE, f(x, 0) = Dirac(x-epsilon)];

pdsolve(pdsys, build)

"Error, (in casesplit/K) this version of casesplit is not yet handling the function: Dirac"

Anybody has an idea what that is? (Using Maple 17) . How can I solve this problem ? 

http://en.wikipedia.org/wiki/Heat_equation

Thanking you on Advance, 

Erez . 

Hi,

I have been looking at some new models of Casio Scientific Calculators and came across with "Fx-115es Plus" Model which seem to have a some sort of simple CAS(Computer Algebra System) built into it.

Two new features which i really liked were

(i) Ability to make any part of the expression inert and simplying the rest.

(ii) Fully Integrated Repeated decimal display for fractions.

I want to ask if there is any builtin commands that can achieve these two effects in maple.

I will give some example for each of these

(i) simplifying say 2^3*2^4 in maple gives 32.

but forexample if i want to make 2 in the bases inert then simplifying the result should give 2^7

if i make 3 inert then the result is 16*2^3

if i make 4 inert then the result is 8*2^4

another example say (2^3)^4 in maple gives 4096

but if i make 2 inert then the result should be 2^12

if i make 3 inert then the result is 16^3

if i make 4 inert then the result is 8^4

In this way it is possible to keep any interesting part of large complex expression unevaluated and simplifying the rest across it to maintain focus on the interesting part.

I know i can try to achieve this effect by using unevaluation quotes but they get messy and harder to track in large nested forms.

Another approach might be to replace the inert parts by explicit undeclared symbols with required assumptions and simplifying, but this is not it.

I know in Maple 18 they have introduced some package called InertForm or something, can it achieve this effect and also mark inert parts of the expression as grey like it is possible for some operators.

(ii) the example for the second is quite obvious, say given the fraction 237/14, evalf of this gives 16.92857143 but a result like 16.9Overscript[285714, _] is more closer to differentiation it from a irrational expansion. Sorry i donot know how to pretty print this here.

Another advantage is when i want to give some large repeating decimal expansion and have maple convert it to fractional form. Currently i have no idea how many times to repeat the decimals explicitly to make maple understand that it is a repeating decimal expansion.

I use "dsolve([ode_1])" command to solve an ODE, and the solution contains lots of " I * ln(cos(m)+I*sin(m)) " expression. As "m" is real, I think this expression is equal to "-m", but the maple command "simplify" do nothing for this expression. Any one who can simplify the expression by using maple ? or ever puzzled by similar problem ?

Hi,

Please I need you to add in the output of my code the order of error defined in the procedure.

Thanks for helping me.

Here, the code.

QuestionNumber2.mw

Hi, I would like to solve this nonlinear problem :

with :

I use the NLPSolve command and i get this error : Error, (in Optimization:-NLPSolve) integer variables are not accepted.

Can you help me ?

Hi:

how obtain value a4 from below equation in maple:

a[0]=1

a[n+2]=a[0]+a[n+1]

I calculate eigenvalues and  eigenvectors of a floating-point square matrix M with the command Eigenvectors(M, output = 'list').  How can I estimate errors of my results?

I have two 6x1 Matrices which are the results of a calculation process in Maple. One with a set of equations and the other one with a set of variables: 

A := [0, f(x6), f(x6), 0, 0, f(x6)];

b := [x1, x2, x3, x4, x5, x6];

I'd like to solve the following system:

for i from 1 to 6 do

eq[i] := A[i] = b[i]:

od;

which is

eq[1] := 0 = x1;

eq[2] := f(x6) = x2;

eq[3] := f(x6) = x3;

...

If I type in the eqations manually, and execute "s := solve({eq[1],..,eq[6]},{x1,..,x6})" everything solves fine.

If I use the "for i from..." - structure, and execute "s := solve({eq[1],..,eq[6]},{x1,..,x6})" I get an empty space as solution.

I've tried to convert both matrices into lists, but it doesn't work.

Could it be that Maple doesnt know that x6 has to be the x6 in the function f(x6) ?

Can anyone tell me how to solve this please?

Hi,

I need your help to fix the error in this code.  many thinks
restart:
pde:=diff(u(t,x),t$2)=diff(u(t,x),x$2)-sin(u(t,x)):
f:=x->x^2:
IBC := {u(0,x)=f(x),u(t,-50)=0,D[2](u)(t, 50)=0,D[1](u)(0, x)=-diff(f(x),x)}:

pds := pdsolve(pde, IBC, numeric):

p1 := pds:-plot(t = 0);
p2 := pds:-plot(t = 1/10);
p3 := pds:-plot(t = 1/2);
p4 := pds:-plot(t = 1);
p5 := pds:-plot(t = 2);
plots[display]({p1, p2, p3, p4, p5}, title = `Sine Gordaon at t=0,0.1,0.5,1,2`);

Hi Maple-Prime-ers!

I have a system of equations, containing 18 variables and 13 equations, making this a 5 degree of freedom (DOF) system.  I would like to analytically solve each of the equations in terms of each of these DOFs.  Normally I would use solve(system, dof_variables) to accomplish this, but it doesn't return anything.  Not even [].

I can solve this system by hand.  I've included a hand-solution involving isolate() and subs() in the attached worksheet.  I'm looking to incorporate this in an optimization algorithm with varying system, so I would like an automated way of doing this.

Does anybody have any suggestions to get solve to work as intended?

3driversys_FD_BRAKE_ICE_GEN.mw

Here is the system I am talking about:

The free variables are:  {FD_T, FD_W, ICE_T, EM2_T, BRAKE_T}

I'm looking for a solution in this form:

For context, I'm designing a work sheet based around quantum tunneling. Currently I'm looking at the boundary conditions.

What I want to be able to do is to set the expression psi[1] equal to psi[2], but only for the value x = 0. Is this possible? I've tried using if statements, and I've considered converting these expressions into functions for this purpose, but I'm not having much luck. 

Thanks

Blanky