ERF(3) BSD Programmer's Manual ERF(3)

## NAME

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

## LIBRARY

libm

## 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**() calculates the error function of x; where
erf(x) = 2/sqrt(pi)*integral from 0 to x of exp(-t*t) dt.
The **erfc**() function calculates 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.
MirOS BSD #10-current April 20, 1991 1

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