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erf(3)


NAME

  erf, erfc - Error functions


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 );


LIBRARY

  Math Library (libm)


STANDARDS

  Interfaces documented on this reference page conform to industry standards
  as follows:

  erf():  XPG4

  erfc():  XPG4

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.


DESCRIPTION

  The erf(), erff(), and erfl() functions return the error function of x,
  where erf(x), erff(x), and erfl(x) equal (2/sqrt(pi)) times the area under
  the curve e**(-t**2) between 0 and x.

  The erfc(), erfcf(),	and erfcl() functions return (1.0 - erf(x)). The
  erfc() function can result in an underflow as x gets large.

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