Subject: Re: bc (1)
To: None <>
From: Phil Nelson <>
List: current-users
Date: 06/21/1996 10:19:15
>does someone familiar with this utility know why it chooses to recode
>series approximations for sin(), cos(), atan() rather than calling the
>(hopefully) functional and accurate library ones?
>i was just grousing that it lacks acos() and asin(), and was slightly 
>horrified to see what its doing.

yes, I know. :)  bc is an arbitrary precision calculator language.
Therefore, one must implement arbitrary precision versions of the
trig functions.  For example, using the C library one would not get
accurate results for:

  scale = 200;  4*a(1);

(which, by the way, prints the first 200 digits after the decimal
point of PI.)

If you write a faster algorithm for computing them accurately to
an arbitrary precision, or write acos() and asin(), please send them
to me.  I'll include them in the next version of GNU bc.

Phil Nelson                       NetBSD:
e-mail:           LPF:       !gifs: