Re: Demostration
- To: mathgroup at smc.vnet.net
- Subject: [mg70453] Re: [mg70369] Demostration
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Mon, 16 Oct 2006 02:36:57 -0400 (EDT)
- Reply-to: hanlonr at cox.net
Reduce[{y^2==x^3+9}, {x,y},Integers]
(x | y) â?? Integers && x >= -2 &&
(y == -Sqrt[x^3 + 9] || y == Sqrt[x^3 + 9])
Select[Flatten[
Table[{{x,-Sqrt[x^3+9]},{x,Sqrt[x^3+9]}},
{x,-2,500}],1],
IntegerQ[#[[2]]]&&#[[2]]^2==#[[1]]^3+9&]
{{-2, -1}, {-2, 1}, {0, -3}, {0, 3}, {3, -6}, {3, 6},
{6, -15}, {6, 15}, {40, -253}, {40, 253}}
Length[%]
10
Bob Hanlon
---- Miguel <mibelair at hotmail.com> wrote:
> How canI to demostrate than the equation y^2=x^3+9 has 10 integer
> solutions?
>
--
Bob Hanlon
hanlonr at cox.net