
ATANH(3)                   UNIX Programmer's Manual                   ATANH(3)

NNAAMMEE
     aattaannhh - inverse hyperbolic tangent function

SSYYNNOOPPSSIISS
     ##iinncclluuddee <<mmaatthh..hh>>

     _d_o_u_b_l_e
     aattaannhh(_d_o_u_b_l_e _x)

DDEESSCCRRIIPPTTIIOONN
     The aattaannhh() function computes the inverse hyperbolic tangent of the real
     argument _x. For a discussion of error due to roundoff, see math(3).

RREETTUURRNN VVAALLUUEESS
     The aattaannhh() function returns the inverse hyperbolic tangent of _x if suc-
     cessful.  On the VAX and Tahoe, if the argument has absolute value bigger
     than or equal to 1, aattaannhh() sets the global variable _e_r_r_n_o to EDOM and a
     reserved operand fault is generated.

SSEEEE AALLSSOO
     acosh(3),  asinh(3),  exp(3),  infnan(3) math(3),

HHIISSTTOORRYY
     The aattaannhh() function appeared in 4.3BSD.

4.3 Berkeley Distribution         May 6, 1991                                1





































