exp

exp

Compute the Exponential Function

Portability: ISO/ANSI C conforming, UNIX compatible

SYNOPSIS
DESCRIPTION
RETURN VALUE
DIAGNOSTICS
EXAMPLE
RELATED FUNCTIONS
SEE ALSO

SYNOPSIS

#include <math.h>

double exp(double x);

DESCRIPTION

exp computes the exponential function of its argument x . The result is e to the x power, where e is the base of natural logarithms, 2.71828 . . ..

The exponential function is the inverse of the natural logarithm and is expressed by this relation:

[IMAGE]

x is a double-precision, floating-point number.

RETURN VALUE

exp returns the exponential function of its argument x , expressed as a double-precision, floating-point number.

DIAGNOSTICS

If x is too large and the ensuing result is so large that it cannot be represented, exp returns HUGE_VAL . In this case, the run-time library writes an error message to the standard error file ( stderr ).

If an error occurs in exp , the _matherr routine is called. You can supply your own version of _matherr to suppress the diagnostic message or modify the value returned.

EXAMPLE

#include <math.h>
#include <stdio.h>

#define XVAL 10.0

main()
{
   double y;

      /* Compute exponent function. */
   y = exp(-XVAL);  
   printf("exp(-%f) = %f\n", XVAL, y);
}

RELATED FUNCTIONS

_matherr

SEE ALSO

Mathematical Functions

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