EXPM1 3CW "09 March 2006" "mathcw-1.00"

Table of contents


NAME

expm1f, expm1, expm1l, expm1w, expm1q, expm1ll, expm1df, expm1d, expm1dl, expm1dll - exponential (base-e) function minus one

SYNOPSIS

cc [ flags ] -I/usr/local/include file(s) -L/usr/local/lib -lmcw [ ... ]

#include <mathcw.h>

extern float expm1f (float x);

extern double expm1 (double x);

extern long double expm1l (long double x);

extern __float80 expm1w (__float80 x);

extern __float128 expm1q (__float128 x);

extern long_long_double expm1ll (long_long_double x);

extern decimal_float expm1df (decimal_float x);

extern decimal_double expm1d (decimal_double x);

extern decimal_long_double expm1dl (decimal_long_double x);

extern decimal_long_long_double expm1dll (decimal_long_long_double x);

NB: Functions with prototypes containing underscores in type names may be available only with certain extended compilers.


DESCRIPTION

Compute the exponential of x, less one, that is e (= 2.718281828...) to the power x, less one.

For arguments of small magnitude, exp(x) - 1 suffers loss of leading significant digits, but the expm1(x) function remains accurate.

Caution: Because the function grows rapidly for arguments of large magnitude, it approaches Infinity fairly quickly.


RETURN VALUES

Return one less than the exponential of the argument, or a NaN if the argument is a NaN.

ERRORS

If the argument is a NaN, return the argument, and set errno to EDOM. If the argument is large enough that the function value is too large to represent (i.e., it overflows), return Infinity, and set errno to ERANGE.

SEE ALSO

exp(3CW), exp2(3CW), exp2m1(3CW), exp8(3CW), exp8m1(3CW), exp10(3CW), exp10m1(3CW), exp16(3CW), exp16m1(3CW), log(3CW), log1p(3CW), log2(3CW), log21p(3CW), log8(3CW), log81p(3CW), log10(3CW), log101p(3CW), log16(3CW), log161p(3CW).