I have tried that, but I get error messages.

AB

I apologize that I have not made my point specifically enough.  I often use Maple as a worksheet on which I do calculations manually, using Maple only to do the tedious stuff.  So, if I have a complicated expression with lots of variables, I might copy & paste it into eval.  This doesn't work if the expression contains a 2nd derivative, expressed conventionally.

The reponse by Robert Israel does not answer my question.  Let's say I have a complicated expression with many variables, one of which is a 2nd derivative, expressed conventionally.  I know the numerical values of these variables, so I use eval to get a numerical answer for the entire expression.  If I express the second derivative in standard math notation, it will be taken as one containing an exponent.  To avoid this, I could simply rename the 2nd derivative as e.g., x.  Is there another way?  I guess not.

Isn't -1 a solution?

I don't want to appear ungrateful, but I was hoping for a simpler answer.  For example,

extrema(3*x^4-4*x^3,{},x);

yields

            {-1, 0}

It would be nice if this command could be modified to consider the endpoints.

When I referred to "the bug," I was referring to the lost files, not the crashing.  But I gather from Alec's answer that lost files is still a problem.  That's surprising since it would seem to be easy to fix; other programs don't have that problem -- e.g., WordPerfect.

Crashing is more difficult to deal with since so many different situations can cause a program to crash.  In my latest crash, I had imported a PDF file, & then I decided to delete it (or maybe I tried to put it on the clipboard -- I forget which), & Maple crashed.

Alla

Sorry to take so long to continue this thread.  The first command is OK but the second

     PDEtools:-declare(u(x));

gives the error message

     'PDEtools' does not evaluate to a module.

How to fix this?

Alla

Kokovidis' solution doesn't work for me.  I am using Windows XP, Maple 9.5, classic interface, & I don't have a red maple leaf or filtered HTML as option on the Export menu.  Is there something that will work for this configuration?

Alla

Answer to your question re Maple's habit of converting even simple decimals to scientific notation while user is inserting standard nonexecutable math into a text region:

Version 9.5
Classic
Windows XP
Worksheet
Insertion via keyboard

Alla

Thanks to Acer for his explanation.  So it appears that the solution can be reduced to two steps:

factor(a^3 - 1);

subs(a = x^(1/3), %);

Alla

Jakubi's code for factoring (x - 1) as the difference of two cubes works fine, but I am having trouble understanding the Maple code.  Could someone please give me a natural language translation, symbol by symbol?

The code is

subs(a=x^(1/3),(factor@subs)(x=a^3,x-1));
                    (1/3)        (2/3)    (1/3)
                  (x      - 1) (x      + x      + 1)

Many thanks.

Alla

Here are the factors I'm looking for:

(x - 1) =  (x^(1/3) - 1)  (x^(2/3) + x^(1/3) + 1)

Alla

Here is a modifed version, said to be graphable:

f(x) =  {  0,     for x irrational
           {  1/b,  for x = a/b a reduced fraction

Alla
           

I first tried limit without RealDomain & got the wrong answer.  Since using RealDomain had cured other problems in this thread, I decided to try it, but got the same wrong answer.  The real question is: How can I get the right answer?

Alla

Why doesn't this work?

> use RealDomain in

   f39 := x -> 4*x^(2/5)-2*x;

   limit(f39(x),x=0,real);

end use;

>

I'm getting zero, but answer should be "undefined," no?

Alla