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Re: To extract the power of variable


On 13 Aug 2004, at 11:55, Tun Myint Aung wrote:

> Hi,
>
>             I want to extract the power of x and y from the polynomial
> function. For example x--2+xy+y2 , I want to get 2 for the first term, 
> 1
> for second term and 2 for last term.
>
> Thanks for help
>
> Tun Myint Aung
>
> Graduate student
>
> National University of Singapore
>
>
First of all, you won't get anywhere with Mathematica unless you learn 
the proper syntax. And the syntax for inputing this polynomial is x^2 + 
x*y + y^2. Secondly, what you are asking for does not make much sense. 
I can't imagine any sensible interpretation of "power of a variable* in 
which the exponent of x y is 1, unless of course you really mean xy to 
be a name of a variable and not a product. But you can get the answer 
you want using:


Exponent[x^2+x y+y^2,#]&/@{x,x y,y}

Out[35]=
{2,1,2}


Assuming that xy really meant the product of x and y (in other words x 
y or x*y)   a more sensible answer is returned by:


First[Transpose[Internal`DistributedTermsList[
      x^2 + x*y + y^2, {x, y}][[1]]]]


{{2, 0}, {1, 1}, {0, 2}}

which means that you have a second power of the first variable, a 
product of terms of degree 1 and a second power of the second variable.



Andrzej Kozlowski
Chiba, Japan
http://www.mimuw.edu.pl/~akoz/


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