freebsd man page for erf

ERF(3)							   BSD Library Functions Manual 						    ERF(3)

NAME
     erf, erff, erfl, erfc, erfcf, erfcl -- error function operators

LIBRARY
     Math Library (libm, -lm)

SYNOPSIS
     #include <math.h>

     double
     erf(double x);

     float
     erff(float x);

     long double
     erfl(long double x);

     double
     erfc(double x);

     float
     erfcf(float x);

     long double
     erfcl(long double x);

DESCRIPTION
     These functions calculate the error function of x.

     The erf(), erff(), and erfl() functions calculate the error function of x; where

	   erf(x) = 2/sqrt(pi)*integral from 0 to x of exp(-t*t) dt.

     The erfc(), erfcf(), and erfcl() functions calculate the complementary error function of x; that is erfc() subtracts the result of the error
     function erf(x) from 1.0.

SEE ALSO
     math(3)

HISTORY
     The erf() and erfc() functions appeared in 4.3BSD.

BSD
								   July 13, 2014							       BSD