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erf(3)

NAME

     erf, erff, erfc, erfcf -- error function operators

LIBRARY

     Math Library (libm, -lm)

SYNOPSIS

     #include <math.h>

     double
     erf(double x);

     float
     erff(float x);

     double
     erfc(double x);

     float
     erfcf(float x);

DESCRIPTION

     These functions calculate the error function of x.

     The erf() and the erff() 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() and the erfcf() functions calculate the complementary error
     function of x; that is erfc() subtracts the result of the error function
     erf(x) from 1.0.  This is useful, since for large x places disappear.

SEE ALSO

     math(3)

HISTORY

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

FreeBSD 5.4			April 20, 1991			   FreeBSD 5.4

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