This might be a trivial question, but I have not been able to find the answer. I am using Maple 2018.

I am working with differential operators acting on real valued functions of a real variable. On the first hand, I want to be able to do simple algebra with these operators. For example, I might want to compute the commutator of two such operators. I have been using the DEtools package, toghether with the 'mult' command to perform such calculations. See the atached file containing a simplified version of what I am doing.

Now, I also want to be able to act with my differential operators on a function, and get the resulting function. 

(a) What command allows me to do that within my framework? (i.e. that of DEtools with the way I have defined and used my operators)

(b) I there a better way to proceed? (i.e. is there a better way to do both algebra with differential operators and to act with them on functions to get the resulting function)

Many thanks

Example.mw

I want to perform a numerical evaluation of sums of integrals of relatively complicated functions. I know about the evalf(Int( )) and evalf(Sum( )) commands to numerically evaluate both sums and integrals individually. My question is: what is the time-efficient way to numerically evaluate a sum of integrals? 

Here is a simplified sketch of what I have.

Say I define my complicated function F of the variable x (which will be integrated over) and of some constant parameter n.

I am interested in numerically evaluating in a time efficient way the following sum of integrals of F:

Where should I apply the evalf() command(s)? Should I go evalf(Sum( evalf(Int( )))) or evalf(Sum( Int())) or sum( evalf(Int( ))), or something else? I am not too worried about the accuracy here: it is for plots mainly. How to make this numercal evaluation fast?

Bonus question. If now I make F also depend on t, and wish to define a function G(t) out of a linear combination of such sums of integrals: is the method the same? I can have G(t) defined numerically with a t dependance. For example:

Thanks a lot!

PS: F is a complicated function in the sense that it is rationnal in some (non-usual) polynomials defined by a Rodrigues Rormula. The integrand has no singularity on the domain of integration. I have Maple 2018.

Hello!

I am working with the Maple 18.02 version. I just want want to perform a basic polynomial expansion using the command "expand" and it does not respond as it should according to what Maple Programming Help says it would. For example:

Maple Programming Help says:

I get:

.

Also, one sees that this isn't even true, as x(x+2) + 1 = x^2 +2x +1, which is not equal to x^2 + 3x +2.

Moreover, maple tells me it is equal..:

What is going on here? I woul like to get the full expanded form (without factors). Also, this is obviously not true, or maybe Maple means something else by x(x+2) +1...

Thank you!