Subject: Maxima 5.9.0 fails to factor this expression.
From: David Ronis
Date: Fri, 17 Aug 2007 10:46:03 -0400
It works here (I'm running 5.12.99rc1, yesterday's cvs update). Factor
generates 2 factors, while factorsum takes me back to the original
expression, more or less. (sorry for the way my e-mail client breaks
the lines messing up he exponents).
David
(%i2) s : (7 x - 1) (1 + 3 z) x
3
(%i3) s1 : expand(s - 1)
(%i4) factor(s1)
3 3 6 2 4 2 2 2
(%o4) (21 x z - 3 x z + 7 x - x - 1) (441 x z - 126 x z + 9 x z
6 4 3 2 6 4 3
2
+ 294 x z - 84 x z + 21 x z + 6 x z - 3 x z + 49 x - 14 x + 7 x
+ x
- x + 1)
(%i5) factorsum(s1)
2 2
(%o5) (x (7 x - 1) (3 z + 1) - 1) (x (7 x - 1) (3 z + 1)
2
(x (7 x - 1) (3 z + 1) +
1) + 1)
(%i6)
On Fri, 2007-08-17 at 23:25 +0900, mrkmhrsh at yahoo.co.jp wrote:
> /* Someone demonstrated this kind of potential bug in maxima. */
>
>
> /* This shows there is a bug in maxima's "factor". */
>
> s : ( 7 * x**2 - 1 ) * ( 3 * z + 1 ) * x ;
>
> s1 : expand ( s**3 - 1 );
>
> factor( s1 );
>
> /* s1 must be factorized, but maxima 5.9.0 failed. */
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