[Maxima-bugs] [ maxima-Bugs-1369689 ] sinh(bigfloat) not accurate

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Bugs item #1369689, was opened at 2005-11-29 21:12
Message generated for change (Comment added) made by rtoy
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Category: Lisp Core
Group: None
>Status: Closed
>Resolution: Fixed
Priority: 5
Submitted By: Raymond Toy (rtoy)
Assigned to: Nobody/Anonymous (nobody)
Summary: sinh(bigfloat) not accurate

Initial Comment:
sinh for small bigfloats is not very accurate:

(%i14) display2d:false;
(%o14) false
(%i15) fpprec:20;
(%o15) 20
(%i16) sinh(1b-8);
(%o16) 9.9999999999999042563B-9
(%i17) x+x^3/3!+x^5/5!;
(%o17) x^5/120+x^3/6+x
(%i18) ev(%,x=1b-8);
(%o18) 1.0000000000000000167B-8

Maxima converts sinh to exponential form and computes
the value using that formula, which is not very
accurate for x near 0.

----------------------------------------------------------------------

>Comment By: Raymond Toy (rtoy)
Date: 2006-01-06 10:27

Message:
Logged In: YES 
user_id=28849

Fixed in CVS:

(%i18) sinh(1b-8);
(%o18) 			   1.0000000000000000167b-8

----------------------------------------------------------------------

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