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Can anyone explain these results?  I m trying to check on a more complicated form of this expression, but cannot proceed without understanding what is occurring in this case.

Hello,

I always used something different from D when using diagonal matrices. Now I learned I can unprotect D.

However, I got this:

> restart; with(LinearAlgebra);
> unprotect(D);
> D := DiagonalMatrix([2, 3]);
> D.D;D^(2);
Error, invalid 'D' operator

Maple does interpret D as a matrix that he can square, but the exponentional notation can't be used as he sees it as some sort of operator?  Can anyone point out my mistake?

I am trying to compute commutator like this [d_t +J_x,d_x+J_t], where d_t and d_x are differential operators, J_x and J_t, which contains generators of group, are some currents on group manifold. terms like this [J_x,J_t] could sovled by physics package, but how to manipulate [d_t,J_x]? How to define operator d_t in order to make the commutator works? and if it works we might have another problem as [d_t,J_x]=[d_t, J^a_x*T_a], where T_a are generators, the result is T_a *d_t(J^a_x...

I am currently taking a course in quantum mechanics using the second edition of McQuarrie's Quantum Chemistry text. I plan to take a QM II course, more concentrating on atomic and molecular spectra. I have been using Mathcad 15, which includes Maple functionality (please pardon my stating the obvious). Mathcad, however, seems to lack functionality (or I have not found it) that would be helpful, like the ability to easily define an operator. Since...

Want to do smth like that:

Hi, all. I'm not too confident in the results of Tolerances. I am very confident in the results of ScientificErrorAnalysis. Sadly, the Tolerances package has an awesome +- operator, while ScientificErrorAnalysis has the bulky Quantity() function. I'd like to define +- to be Quantity, something akin to this:

`&+-` := (a,b)->Quantity(a,b);

Sadly, 

1+`&+-`(2);

To answer this question you need to create a Maple function using Maple's arrow (->) notation.

Your function should take a Maple list of real numbers as its input and return the smallest cosine from that list.

Enter your function in the box below.

Your Answer: op(1,sort(map(cos,x)))

Comment: No solution is given for this question.

Can anyone tell me how my answer is incorrect, or more importantly, what the correct answer is?