## 453 Reputation

5 years, 334 days

## convert/exp...

Hi,

Maple result seems correct to me. The point is that the returned sum is a Dirac comb. Writting the result as a sum of exp or a sum of Dirac is a matter of choice depending of what you need. Using convert/exp might help:

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Considering the Dirac comb

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One has the relation

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And finally

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Note that the reciprocal conversion is not (yet) supported

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## Possibly Physics:-Fundiff...

Hi,

For deriving an equation in Physics, Fundiff is often the good approach. This should give the result:

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## Define quantum operators and use Commuta...

Hi,

In order to have * redefined, you need first to define quantum operators for instance. Then [a,b] has the same meaning whether Physics is loaded or not. I guess you'd like to use the commutator. For that purpose, just use "Commutator":

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## anticommutativeprefix = {x, y}...

Hi,

In your case, you should rather use Setup(anticommutativeprefix = {x, y}), not "noncommutativeprefix". Then, it is unnecessary to specify "algebrarules={%AntiCommutator(x,x)=0, %AntiCommutator(y,y)=0}" as it will be automatically the case.

Finally, Maple's result:

AntiCommutator(x,y)=0

seems correct to me. As x and y anticommute, x*y + y*x = x*y - x*y = 0.

## Physics differentialoperators...

Hi,

A possible way is to define a formal differential operator within the Physics package. It can be define with an arbitrary function and trigged at will. For an exemple, have look at:

https://www.mapleprimes.com/posts/208710-Quantum-Commutation-Rules-Basics

## Component...

Hi,

Using "Component", it is possible to reconstruct a Vector:

V := Vector([seq(Component(q_, k), k = 1 .. 3)])

Component2Vector.mw

## Parentheses...

Try -3 - (-5) or  4*(-10), It should work as expected.

However, I agree that an expression like -3 - -5 should work without parentheses in Maple, mathematically the expression is correct, surprising. Entering -3-+-5 or 4*-10 in Matlab gives the expected result.

## Alias and Physics:-Latex...

Hi,

I think that using the new Physics:-Latex with alias, there is even no need for replacing.

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 x \left( t \right) ={\it \_C1}\,{{\rm e}^{t}}+{\it \_C2}\,{{\rm e}^{-{ \frac {t}{2}}}}\sin \left( {\frac {\sqrt {3}t}{2}} \right) +{\it \_C3} \,{{\rm e}^{-{\frac {t}{2}}}}\cos \left( {\frac {\sqrt {3}t}{2}}  \right)
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 x \left(t \right) = c_{1} {\rm e}^{t}+c_{2} {\rm e}^{-\frac{t}{2}} \sin \left(\frac{\sqrt{3} t}{2}\right)+c_{3} {\rm e}^{-\frac{t}{2}} \cos \left(\frac{\sqrt{3} t}{2}\right)
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Hi,

## Differential operator...

You might define a differential operator

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## Setup(quantumoperators = V)...

Hi,

With Physics package, to get this feature, V should be declared as a quantum operator. Also, use Dagger instead of Transpose, or V_^*.

restart;
with(Physics);
with(Physics[Vectors]);
Setup(quantumoperators = V);
V_*Dagger(V_);

This question is related:

Hi,

L := [1, 2, 3, 4, 5];
L := [1, 2, 3, 4, 5]

15

## Restart...

Hi,

I have the same sometime. Just enter "restart" and this should load the last version, even if the message is the same. Otherwise, just close your worksheet and reopen it, it should work fine.

## Several ways...

Hi,

There are several ways. You can use "indets" to extract the variable of an expression, and then "select" according particular properties. For instance, assuming x and y have a t depedency, while A and B are independent of that parameter:

EE := (x(t)/A)^2 + (y(t)/B)^2 = 1;
2       2
x(t)    y(t)
EE := ----- + ----- = 1
2       2
A       B

FF := indets(EE);
FF := {A, B, t, x(t), y(t)}

select(u -> type(u, freeof(t)), FF);
{A, B}

## Close the Palette...

Hi,

In addition to Edgardo's recommendations, you could try to close the palettes (left Panel). There is a known issue at startup for Maple 2020 involving those palettes. Once Maple has started again, you can reopen the required palettes.

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