## 217 Reputation

18 years, 17 days

## How to substitute a function...

The following example tries to do the same thing two different ways.

Calling a procedure "M1" directly by name works fine.

Calling the same procedure by substitution fails to substitute, and when the substrituion is forced using "apply" I get an error message.

Why does the substitution not work, and where is the error?

Because of the complexity of my problem, I need to use substitute (or anything else equivalent) instead of directly calling the procedure by name.

## Is this a bug and has it been fixed?...

Maple

Hi:

I have justdiscovered that the following "simplify" command gives the wrong answer on Maple 11. Could someone please check to determine if Maple 14 does any better?

> S1:=Sum(1/GAMMA(j+1)/GAMMA(2-j)*GAMMA(1+a-c+j)*GAMMA(1+a-b+j)/GAMMA(a-
> 1+j)*GAMMA(-2+b+c-j+n-a),j = 0 .. 1);
> Ans1:=simplify(S1);

1
-----
\

## How do I distribute the Sum function ove...

Maple

Hi:

I have a number of functions all enclosed inside the Sum functionin the  following form:

Test:=Sum(f1(n)+f2(n)),n=1..infinity);

Each of the functions f1, etc are fairly complicated, and there are more than two, but this example will do.

How do I get Maple to expand Test into the form:

Test:=Sum(f1(n),n=1..infinity) + Sum(f2(n),n=1..infinity);

I've tried every combination of expand, simplify, combine collect, that I can think of - nothing works.

## further on premature evaluation, substit...

Thank you

Your answer makes sense if Maple evaluates from innermost to outermost, so the substitution in T2c takes place AFTER Test is evaluated with a symbolic value of "n".

But it doesn't explain why the "assuming" examples work - or don't work. If "Test" is evaluated first, then none of the examples should work; if the assumption is passed through "simultaneously" (whatever that means), then the wording of the error message doesn't make sense...

## substitution and assuming...

Maple

The attached file demonstrates that a substitution into a piecewise function appears (sometimes) to execute the wrong half of the function.

If I use "assuming" instead of substitution, the assumption appears to get through to the piecewise function, but only sometimes.

I don't understand why this happens. Can anyone clarify what is going on? See below.

Thank you.

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