exp(3M)                                                   exp(3M)



NAME
     exp, log, log10, pow, sqrt - provide exponential, logarithm,
     power, and square root functions

SYNOPSIS
     #include <math.h>

     double exp(x)
     double x;

     double log(x)
     double x;

     double log10(x)
     double x;

     double pow(x, y)
     double x, y;

     double sqrt(x)
     double x;

DESCRIPTION
     The exp function returns e raised to the power of x.

     log returns the natural logarithm of x.  The value of x must
     be positive.

     log10 returns the logarithm base ten of x.  The value of x
     must be positive.

     The pow function returns x raised to the power of y.  If x
     is zero, y must be positive.  If x is negative, y must be an
     integer.

     sqrt returns the nonnegative square root of x.  The value of
     x may not be negative.

STATUS MESSAGES AND VALUES
     The exp program returns HUGE when the correct value would
     overflow, or 0 when the correct value would underflow, and
     sets errno to ERANGE.

     log and log10 return -HUGE and set errno to EDOM when x is
     nonpositive.  A message indicating DOMAIN error (or SING
     error when x is 0) is printed on the standard error output.

     pow returns 0 and sets errno to EDOM when x is 0 and y is
     nonpositive, or when x is negative and y is not an integer.
     In these cases a message indicating DOMAIN error is printed
     on the standard error output.  When the correct value for
     pow would overflow or underflow, pow returns +HUGE or 0



January 1992                                                    1

exp(3M)                                                   exp(3M)



     respectively, and sets errno to ERANGE.

     sqrt returns 0 and sets errno to EDOM when x is negative.  A
     message indicating DOMAIN error is printed on the standard
     error output.

     These error-handling procedures may be changed with the
     function matherr(3M).

SEE ALSO
     intro(2), hypot(3M), matherr(3M), sinh(3M)












































2                                                    January 1992