List quastion

Hi There,

I want to make a predicate that do the following:

poly([1,2,3],2,Z).

Z= [2,4,6].

so it multiply the 2 with the list.

and another predicate that do the following:

prod_poly([1,2,3],[3,2,1],Z).

Z= [3,9,4,8,3]

this one see the elements in the list as 1 number so in this example
it will multiply 123 * 321   and return the answer in list Z.  this
one is hard i hope someone can tell me how.

Thanks in advance
Kimos

Dear Kimos,

> prod_poly([1,2,3],[3,2,1],Z).
>
> Z= [3,9,4,8,3]
>
> this one see the elements in the list as 1 number so in this example
> it will multiply 123 * 321   and return the answer in list Z.  this
> one is hard i hope someone can tell me how.
>

Hint: How do you multiply polynomials?

Best wishes,

Bill

"kimos" <urdad@hotmail.com> a écrit dans le message de news:
ae02c0a1.0410100403.3094ca9a@posting.google.com...
> Hi There,
>
> I want to make a predicate that do the following:
>
> poly([1,2,3],2,Z).
>
> Z= [2,4,6].
>
> so it multiply the 2 with the list.


poly([],[]).
poly([X|L],[X2|L2]):-
X2 is X*2,
poly(L,L2).

"ezze" <ezze@wanadoo.fr> wrote in message news:<4169565a$0$28826$8fcfb975@news.wanadoo.fr>.
.
> "kimos" <urdad@hotmail.com> a écrit dans le message de news:
> ae02c0a1.0410100403.3094ca9a@posting.google.com... 
>
>
> poly([],[]).
> poly([X|L],[X2|L2]):-
>     X2 is X*2,
>     poly(L,L2).

ezze thanks for replay but this isnt what i want. my poly is with 3 inputs
poly([],[],[]).


Bill Spight i dont get your hint. how do you multiply polynomials ?

hope someone can help  im realy stuck with thos 2 predicates

Dear kimos,

> Bill Spight i dont get your hint. how do you multiply polynomials ?

Example:

(5x^2 + 3x + 2) * (-4x^2 - 2x + 1) = y

prod_poly([5, 3, 2], [-4, -2, 1], Y).

Now the example you gave is not exactly that, but appears to assume that
x = 10, and carries partial products. However, given the name,
"prod_poly", I suspect that the meat of your assignment is to write a
program to multiply polynomials, represented as lists. That is something
that you learned to do in high school, I suspect.

Best wishes,

Bill

 
>
> ezze thanks for replay but this isnt what i want. my poly is with 3 inputs
> poly([],[],[]).
>

sure,
poly([],_,[]).
poly([X|L],V,[X2|L2]):-
X2 is X*V,
poly(L,V,L2).

its the first predicate youre looking for (in your first message)

Bill Spight <bspight@pacXbell.net> wrote in message news:<416AE319.CF646229@pacXbell.net>..
.
> Dear kimos,
> 
>
> Example:
>
>     (5x^2 + 3x + 2) * (-4x^2 - 2x + 1) = y
>
>     prod_poly([5, 3, 2], [-4, -2, 1], Y).
>
> Now the example you gave is not exactly that, but appears to assume that
> x = 10, and carries partial products. However, given the name,
> "prod_poly", I suspect that the meat of your assignment is to write a
> program to multiply polynomials, represented as lists. That is something
> that you learned to do in high school, I suspect.
>
> Best wishes,
>
> Bill


Dear Bill

thanks for the replay.

i solved the first predicate afer hard work

poly([],N,[]).
poly([X|L],N,[X2|L2]):-
X2 is X*N,
poly(L,L2).

but im still stuck with the second one as u mention "multiply
polynomials, represented as lists"  they didnt learned prolog im doing
this for my graduation project.

Dear kimos,

> but im still stuck with the second one as u mention "multiply
> polynomials, represented as lists"

Did you take algebra, and learn how to multiply (x^2 - x + 3) and (2X^2
+ 3x - 10)? What steps did you take to do that multiplication?

If you did not take algebra, think back to when you learned arithmetic.
What steps did you take to multiply  234 and 637? They are equvalent to
(2x^2 + 3x + 4) times (6x^2 + 3x + 7), where x = 10.

Good luck!

Bill

Bill Spight <bspight@pacXbell.net> wrote in message news:<416C3295.F1F417B7@pacXbell.net>..
.
> Dear kimos,
> 
>
> Did you take algebra, and learn how to multiply (x^2 - x + 3) and (2X^2
> + 3x - 10)? What steps did you take to do that multiplication?
>
> If you did not take algebra, think back to when you learned arithmetic.
> What steps did you take to multiply  234 and 637? They are equvalent to
> (2x^2 + 3x + 4) times (6x^2 + 3x + 7), where x = 10.

It could be a little bit easier to solve the problem by representing
(2x^2 + 3x + 4) with [4,3,2] ...

sangai@freemail.hu (Sangai) wrote in message news:<f3c0ce7.0410122226.296b1e63@posting.goog
le.com>...
> Bill Spight <bspight@pacXbell.net> wrote in message news:<416C3295.F1F417B
7@pacXbell.net>... 
>
> It could be a little bit easier to solve the problem by representing
> (2x^2 + 3x + 4) with [4,3,2] ...


Thats true and thats what im trying to do  represent it as [4,3,2].
but i cant find any answer for it