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#include <math.h> double expm1(double x); |
This function computes the value of e^x - 1, the exponential of
x minus 1, where e is the base of the natural system of
logarithms, approximately 2.718281828. The result is more accurate than
exp(x) - 1 for small values of x, where the latter method
would lose many significant digits.
e raised to the power x, minus 1. If the value of x is
finite, but so large that its exponent would overflow a double,
the return value is Inf, and errno is set to
ERANGE. If x is either a positive or a negative infinity,
the result is either +Inf or -1, respectively, and errno
is not changed. If x is a NaN, the return value is
NaN and errno is set to EDOM.
| ANSI/ISO C | No |
| POSIX | No |