expm1, expm1f---exponential minus 1Synopsis
#include <math.h> double expm1(double x); float expm1f(float x);
Description
expm1 and expm1f calculate the exponential of x
and subtract 1, that is,
e raised to the power x minus 1 (where e
is the base of the natural system of logarithms, approximately
2.71828). The result is accurate even for small values of
x, where using exp(x)-1 would lose many
significant digits.
Returns
e raised to the power x, minus 1.
Portability
Neither expm1 nor expm1f is required by ANSI C or by
the System V Interface Definition (Issue 2).
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