Ilya Zakharevich on Mon, 12 May 2003 17:08:38 -0700


[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

Re: CVS: seriesprecision too large


On Sat, May 10, 2003 at 03:29:23PM -0700, Ilya Zakharevich wrote:
> ? default(seriesprecision,9)
>    seriesprecision = 9 significant terms
> ? sin(x+y)
>       /     1 3    1  5    1   7     1    9     10  \
> %2 =  | y - -y  + ---y  - ----y  + ------y + O(y  ) | +
>       \     6     120     5040     362880           /
> /     1 2   1  4    1  6     1   8      1    10     11  \
> | 1 - -y  + --y  - ---y  + -----y  - -------y  + O(y  ) | x +
> \     2     24     720     40320     3628800            /

OK, I can believe it is an artefact of the used algorithm.  But watch this:

? sin(x*y/(x+y))
  ***   division by zero in gdiv, gdivgs or ginv

Ilya