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expm1 (3)
EXPM1(3) Linux Programmer's Manual EXPM1(3)
NAME
expm1, expm1f, expm1l - exponential minus 1
SYNOPSIS
#include <math.h>
double expm1(double x);
float expm1f(float x);
long double expm1l(long double x);
Link with -lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
expm1(), expm1f(), expm1l(): _BSD_SOURCE || _SVID_SOURCE ||
_XOPEN_SOURCE >= 500 || _ISOC99_SOURCE; or cc -std=c99
DESCRIPTION
expm1(x) returns a value equivalent to 'exp (x) - 1'. It is computed
in a way that is accurate even if the value of x is near zero--a case
where 'exp (x) - 1' would be inaccurate due to subtraction of two num-
bers that are nearly equal.
CONFORMING TO
BSD, C99. The float and long double variants are C99 requirements.
SEE ALSO
exp(3), log(3), log1p(3)
2007-07-26 EXPM1(3)
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