! :folding=indent:collapseFolds=0:

! $Id$
!
! Copyright (C) 2004 Slava Pestov.
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IN: math
USE: kernel
USE: math
USE: math-internals

! Inverse trigonometric functions:
!    acos asec asin acosec atan acot

! Inverse hyperbolic functions:
!    acosh asech asinh acosech atanh acoth

: acosh dup sq pred sqrt + log ;
: asech recip acosh ;
: asinh dup sq succ sqrt + log ;
: acosech recip asinh ;
: atanh dup succ swap pred neg / log 2 / ;
: acoth recip atanh ;
: <=1 ( x -- ? ) dup complex? [ drop f ] [ abs 1 <= ] ifte ;
: asin dup <=1 [ fasin ] [ i * asinh -i * ] ifte ;
: acos dup <=1 [ facos ] [ asin pi/2 swap - ] ifte ;
: atan dup <=1 [ fatan ] [ i * atanh i * ] ifte ;
: asec recip acos ;
: acosec recip asin ;
: acot recip atan ;