On Wed, 18 May 2011, Jaime Villate wrote:
> On Wed, 2011-05-18 at 16:30 +0200, Hugo Coolens wrote:
>> What is wrong with following sequence of commands?
>>
>> eq1:x1=(-b+sqrt(b^2-4*c))/2;
>> eq2:x2=(-b-sqrt(b^2-4*c))/2;
>> solut:solve([eq1,eq2],[b,c]);
>>
>> I expected to see b=-(x1+x2)/2 ... but I just get []
> Hi Hugo,
> you mean b = - (x1+x2)
yes, you're right of course
> I got the correct answer using a dirty hack:
>
>
> (%i7) solut:solve([eq1+eq2,eq1*eq2],[b,c]);
> (%o7) [[b = -x2-x1,c = x1*x2]]
>
thanks!
> Cheers,
> Jaime
>
>
>