## two different answers just like a bug for operator...

Dear,i meet a problem in Physics package.i can't find why i got two different answers.

restart; with(Physics); Setup(mathematicalnotation = true);Setup(op = {C});

Cp := Dagger(C);

alg := %Commutator(Cp, C) = -1;

Setup(alg)

S := sqrt(N-(Dagger(C)+sqrt(N)*conjugate(eta))*(C+sqrt(N)*eta)):

eq1 := collect(expand(op(1, S)), N):

xi = op(1, eq1);

f := map(simplify, map(proc (x) options operator, arrow; x*sqrt(xi) end proc, convert...

## Add duplicates in sparse Matrices...

Hello,

I have a small Finite Element program in Maple. I want to accelerate the Matrix assembly. For Matlab this works like described here (http://milamin.sourceforge.net/technical-notes/sparse-matrix-assembly) under "Triplet Sparse Storage". There, two indexing Vectors are used to place the values into a sparse Matrix with the Matlab function sparse. If index pairs are duplicate, they are added.

Now I want to ask if this is also possible in Maple?...

## Remove same (sepcific) elements from Vectors...

Hi all,

Say i have two Vectors:

V1:=Vector(2,[a,b]);

V2:=Vector(4,[d,b,e,a]);

and how do I get

V3:=Vector([d,e]);

?? I currectly use a crude way using 'set' operations:

V3:=convert(V2,set) minus convert(V1,set);

V3:=convert(V3,Vector); # Does not work straightford, so

V3:=convert(V3,list):
V3:=convert(V3,Vector); # Which works,

Also, is there a strightforward way to which elements are the same and their indices?

## Maple 17 causes SC/32A fatal errors and prompts to...

This is a very strange and specific issue I am having with any Windows x86 vm after having installed Maple 17.

Before installing Maple 17 (and also AFTER installing it, before the reboot), I can open a command window while logged in as the local administrator and successfully issue a command like:

sc config BDESVC start= disabled

## Can't solve equation without returning _Z...

Hi,

I'm dealing with an iterated function (logistic map) where f(x)=s*x*(1-x) where the s is a general parameter between 1 and 4 inclusive, and it's fourth return map, or f(f(f(f(x)))) or f^[4](x).

h:x->f(f(f(f(x))))

What I'm trying to do hinges on evaluating this:

solve(h(x)=x,x);

a

## dsolve invalid input when plotting...

ode := diff(x(t), t, t) = 1^2*(cosh(x(t))-1)/cosh(x(t))

ics := x(0) = 2, (D(x))(0) = 0

xs := dsolve({ics, ode})

plot(xs, t = 0 .. 3)

why do i get this error?

Error, invalid input: plot expects its 1st argument, p, to be of type {set, array, list, rtable, algebraic, procedure, And(`module`, appliable)}, but received x(t) = RootOf(Int(1/(-4*arctan(exp(_a))+4*arctan(exp(2))-4+2*_a)^(1/2), _a = _Z .. 2)+t)

## Help me about programming ?...

Can you help me how to program about the interference of wave on the water surface in Maple ?

## How can I find the surface area of a normal chicke...

How can I find the surface area of a normal chicken egg? http://math.stackexchange.com/questions/407310/how-can-i-find-the-surface-area-of-a-normal-chicken-eggPlaying replies to the topic in Mathematics Stack Exchange:_SurfaceAreaChickenE.zipGracias to Acer and Carl Love for your answers.

## smartplot vs implicitplot...

Dif_Out_plot.mwWhy this difference in the results of the graphics?There are differences between the command smartplot and the command smartplot implicitplot, to display the graph of the function.Following the line of site: web

## Getting an error with a commutator/algebra rule...

Hi,

iam trying to define a commutator rule (using the Physics package) but iam getting an error i do  not understand.

I have (quantum) operators like this: Aij  i and j are numbers from 0 to 3

The commutator relation i want to define is: [Aij,Akl] = Ailδjk - Akjδil

My worksheet looks like this:

## ODE with events...

HI,is it possible to solve the ODE system (that I have uploaded) by adding events at a certain timestep, instead of reformulating the system for each step.The ODE system expresses two coupled movements y(t) and X(t). The current position of y(t) is controlled by a parameter which depends on values calculated in the previous step, while changing the sign for each step.Thank you!

## Error in executing my function...

Hi every one

I'm new to maple programming so my question might be boring. I'm trying to solve the higher order kernel generation function which appears in B. Hansen (Econometric Theory, 2005). The quation is