1*61285Sbostic.\" Copyright (c) 1985, 1991, 1993 2*61285Sbostic.\" The Regents of the University of California. All rights reserved. 348920Scael.\" 449229Scael.\" %sccs.include.redist.roff% 548920Scael.\" 6*61285Sbostic.\" @(#)atanh.3 8.1 (Berkeley) 06/04/93 748920Scael.\" 848920Scael.Dd 948920Scael.Dt ATANH 3 1048920Scael.Os BSD 4.3 1148920Scael.Sh NAME 1248920Scael.Nm atanh 1348920Scael.Nd inverse hyperbolic tangent function 1448920Scael.Sh SYNOPSIS 1548920Scael.Fd #include <math.h> 1648920Scael.Ft double 1748920Scael.Fn atanh "double x" 1848920Scael.Sh DESCRIPTION 1948920ScaelThe 2048920Scael.Fn atanh 2148920Scaelfunction computes the inverse hyperbolic tangent 2248920Scaelof the real 2348920Scaelargument 2448920Scael.Ar x . 2548920ScaelFor a discussion of error due to roundoff, see 2648920Scael.Xr math 3 . 2748920Scael.Sh RETURN VALUES 2848920ScaelThe 2948920Scael.Fn atanh 3048920Scaelfunction 3148920Scaelreturns the inverse hyperbolic tangent of 3248920Scael.Ar x 3348920Scaelif successful. 3448920ScaelOn the 3548920Scael.Tn VAX 3648920Scaeland 3748920Scael.Tn Tahoe , 3848920Scaelif the argument has absolute value 3948920Scaelbigger than or equal to 1, 4048920Scael.Fn atanh 4148920Scaelsets the global variable 4248920Scael.Va errno 4348920Scaelto 4448920Scael.Er EDOM 4548920Scaeland 4648920Scaela reserved operand fault is generated. 4748920Scael.Sh SEE ALSO 4848920Scael.Xr acosh 3 , 4948920Scael.Xr asinh 3 , 5048920Scael.Xr exp 3 , 5148920Scael.Xr infnan 3 5248920Scael.Xr math 3 , 5348920Scael.Sh HISTORY 5448920ScaelThe 5548920Scael.Fn atanh 5648920Scaelfunction appeared in 5748920Scael.Bx 4.3 . 58