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How do I "clear" an array?

I need to do the following. Suppose I have an array, c[ ]. I need to be able to specialize the elements of this array, and then later "clear" the elements, making them indeterminates again. I attempted to do this by creating a temporary holding array

i:='i': for i from 1 to 5 do d[i]:=c[i] end do;
i:='i': for i from 1 to 5 do c[i]:=i end do;
i:='i': for i from 1 to 5 do c[i]:=d[i] end do;
 

I expected and want the output to be

c[0] c[1] c[2] c[3] c[4] c[5] 1 2 3 4 5 c[0] c[1] c[2] c[3] c[4] c[5]

Here's a little test double loop

for i from 1 to 2 do

for j from 1 to 2 do

A[i,j]:=Binomial[i+j,i];

end do;

end do;

I would like to get ANYTHING to output. I get NOTHING, no matter WHAT variations I make. I can output when the loop is just a SINGLE nest. But, as soon as I embed that nest inside a second nest - NOTHING outputs.

 

Are there any commands which will allow me to create zero-based arrays in Maple?

I have a linear recursion, in 4 variables,

c[i,j,k,l]

In Math Mode in a Maple worksheet,
how do I type something such as

L := [1, 2, "abc", "a", 7.0, infinity];
for x in L do
if type(x, 'string') then
print(x);
break
end if
end do

on multiple lines?

Also, please show me in the online Help menu
the explanation for how one makes such line breaks
without setting off execution.

I got Maple last August. I have searched the online Help
menu for any mention of a line break but have not found it.

Thank you.

resolvent's picture

How Do I Find a Particular Theorem?

How do I locate a particular theorem in Linear Algebra that I need for my research?

I have been to conferences which seriously discussed a unified and universal bank of all known math theorems. Theoretically, all proven math theorems could be connected logically: A implies B. But, in reality, most proven math theorems are scattered throughout the literature.

I have no access to a university with math journals.
I might be able to do inter-library loan at my local community county college here in the United States. But, that may take a long time. I have no paid job. My earned income is only from social security disability.

Hi, again.
Another applied problem arose today which requires me to compute all the roots of a polynomial
with real coefficients. The degree needs to be left arbitrary.

I only see vague references on the internet to the very abstract, symbolic "formula"
(if one wishes to call it that) for all the roots of a polynomial in terms of siegel
(siegal? seagel?) elliptic modular functions. No one ever seems to try to use it.

The only person I know who ever wrote out the formula was Hiroshi Umemura, professor
from Nagoya University in Japan. I actually contacted him once, back in 1994. But

When I used Mathematica in graduate school, I would ubiquitously specialize
a variable and then later "un"specialize it. Specifically, for example, I would write

v:= x^3;

Then, later, when I wanted the symbol "v" to be left symbolically, I would redefine it
with nothing following the definition

v:=;

I forgot the exact syntax, but it was something like this.
But, I cannot find this feature in Maple. Yet I badly need it.
Currently, for me to recover the use of a symbolic variable name like 'v',
I have to CLOSE DOWN MY DOCUMENT and REOPEN IT!

Secondly, in Mathematica, I easily evaluated the "independent" variable to a value

resolvent's picture

Lengths of Lists

What is the command which returns the length of a list?
i.e. length of [1,2,3] is 3 ?

More importantly, please tell me where in the help menu this command is listed. Thank you.

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