exp
exponential functions
You're viewing an older version of this page (#4004). View the current version.
INTERFACE
#include <math.h>
double exp ( double x )
long expl ( long double x )
float expf ( float x )
double exp2 ( double x )
long exp2l ( long double x )
float exp2f ( float x )
double expm1 ( double x )
long expm1l ( long double x )
float expm1f ( float x )DESCRIPTION
The exp function computes , the base-e exponential of x.
The exp2 function computes , the base-2 exponential of x.
The expm1 function computes the base-e exponential of x, minus 1, accurately even for very small values of x.
Example 1
\code #include <stdio.h> #include <math.h> int main(void) { double result, x = 4.34; result = exp(x); printf("'e' raised to the power of %.2lf (e^%.2lf) = %.2lf
", x, x, result); return 0; } \endcode
Output:
'e' raised to the power of 4.34 (e^4.34) = 76.71SPECIAL VALUES
exp ( ±0 ) and exp2 ( ±0 ) return 1.
exp ( -∞ ) and exp2 ( -∞ ) return +0.
exp ( +∞ ) and exp2 ( +∞ ) return +∞.
expm1 ( ±0 ) returns ±0.
expm1 ( -∞ ) returns -1.
expm1 ( +∞ ) returns +∞.
For all these functions, a range error occurs if the magnitude of x is too large.
SEE ALSO
STANDARDS
The exp, exp2 and expm1 functions conform to ISO/IEC 9899:1999(E).