## 5701 Reputation

8 years, 304 days

## how to divide or split an execution grou...

I am not able to find way to do this very basic and common operation.

I use worksheet mode, and many times I'd like to split/divide a large execution group I've build of some code to 2 execution groups at some place. i.e. I'd like to point my mouse at a line and say divide here. Here is an example:

I see only the options Insert->Execution group-> After Cursor or Before cursor. Both of which do not do what I want. I want to divide it at that point.  So what I end up doing is to make a new execution group manually (using the Insert command), then go back and cut and paste the code I want in the new group.

I hope there is an option to do this. I do these sorts of things all the time when using Mathematica, which has Divide cell, Merge cells and other options. A cell in Mathematica is similar to execution group in Maple. Are there other options to maniuplate execution groups other insert before/after cursor that I might have missed? I am using 17.02 on windows 7.

Please note, I only use worksheet mode.

## how to (1/2) factor from this expression...

intEq:= 2*cosh(x)-sinh(x)-(2-x)= 1 + int( (2-x+t)* phi(t),t=0..x):
intsolve(intEq,phi(x));

I'd like to extract the (1/2) out, so that it shows as (1/2)*exp(x/2) *  (cosh(x/2) - etc....)

Any recommended way to do it? My attempts did not work well. I am newbie in Maple. Thanks.

## any short cut to convert a set to a Vect...

accroding to http://www.maplesoft.com/support/help/Maple/view.aspx?path=convert%2fVector  set can't be converted to Vector.

So I have to convert set to list, then convert the list to a Vector:

a:={1,2}:
convert(convert(a,list),Vector);

I was wondering if there is a short way to type this or a command that I might have overlooked, as it seems too much typing for such a common operation. (it would be nice if convert would support this automatically by doing the above so one can just type convert(a,Vector).  I am using Maple 17.02. I googled around, and did not find anything.

On a side note: The reason I ask, is that dsolve and many other operations like it, return the solutions as a set. Many times I need to multiply this by a Matrix. Hence the conversion need.

## How to make a Clear( var1, var2, ....) f...

It seems Maple has no Clear(variable); function build in, and one must type

variable := 'variable`;

for each variable to be cleared. This is a little too verbose. In Mathematica one types "Clear[variable1,variable2]" which requires much less typing than the Maple way of doing it. (About 1/2 as much, if one has to clear few variables each time).

Doing restart is not a good solution all the time, since that will clear everything.

Strange why Maple can not provide such a function, and inside it, it can do these calls.

So, I was wondering if someone has written such a function. I can try to write one myself, but I am not very good in Maple, and I think a professionally written one by an expert would be more robust and will do more checking as needed to make sure it works correctly.

So, my question is, why Maple does not provide such a function as build-in? And does one know of a good implementation of one that exist?

## how to apply dsolve to set of diff. equa...

Suppose one sets a system of differental equations in vector form, say 2 ODE's, like this:

restart;
with(LinearAlgebra):
ode:=Vector([diff(x(t),t),diff(y(t),t)])=Vector([2*x(t)+y(t),3*y(t)-x(t)]);

Then to solve these, what would be an easy way to do it, without having to rewrite them again manually as a set, as what one would normally do. Clearly one needs to map dsolve, and also convert the vectors to a set somewhere? I am not able to get the syntax right.

Is there an easy way to automatically convert/rewrite the above to

ode2:= diff(x(t),t)=2*x(t)+y(t)  ,   diff(y(t),t)=3*y(t)-x(t);

so that I can just do

dsolve({ode2},{x(t),y(t)});

Or, a way to map dsolve directly into the first from as shown?( the Vector = Vector form).

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