exp(3M)                                                             exp(3M)

NAME
     exp, expf, expm1, cbrt, log, logf, log10, log10f, log1p, pow, powf,
     sqrt, sqrtf - exponential, logarithm, power, square root functions

SYNOPSIS
     cc [flag ...] file ... -lm [library ...]

     cc -O -Ksd [flag ...] file ... -J sfm [library ...]

     #include <math.h>

     double exp(double x);

     float expf(float x);

     double expm1(double x);

     double cbrt(double x);

     double log(double x);

     float logf(float x);

     double log10(double x);

     float log10f(float x);

     double log1p(double x);

     double pow(double x, double y);

     float powf(float x, float y);

     double sqrt(double x);

     float sqrtf(float x);

DESCRIPTION
     exp() and expf() return e^x.

     expm1() computes e^x-1.0.

     cbrt() returns the cube root of x.

     log() and logf() return the natural logarithm of x. The value of x
     must be positive.

     log10() and log10f() return the base ten logarithm of x. The value of
     x must be positive.






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exp(3M)                                                             exp(3M)

     log1p() computes loge(1.0 + x). The value of x must be greater than
     -1.0.

     pow() and powf() return x^y. If x is 0, y must be positive. If x is
     negative, y must be an integer.

     sqrt() and sqrtf() return the non-negative square root of x. The value
     of x may not be negative.

RESULT
     exp() and expf() return HUGEVAL when the value would overflow, or 0
     when the value would underflow. errno is set to ERANGE.

     If x is NaN, then expm1 returns NaN and errno may be set to EDOM. If x
     is positive infinity, expm1() returns positive infinity. If x is nega-
     tive infinity, expm1() returns -1.0. If the value overflows, expm1()
     returns HUGEVAL and may set errno to ERANGE.

     The value of expm1(x) may be more accurate than exp(x)-1.0 for small
     values of x.

     The expm1() and log1p() functions are useful for financial calcula-
     tions of ((1+x)^n-1)/x, namely:

          expm1(n * log1p(x))/x

     when x is very small (for example, when calculating small daily
     interest rates). These functions also simplify writing accurate
     inverse hyperbolic functions.

     log(), logf(), log10(), and log10f() return -HUGEVAL and set errno to
     EDOM when x is non-positive. A message indicating DOMAIN error is out-
     put on standard error.

     Upon successful completion, log1p() returns the natural logarithm of
     1.0 + x. If x is NaN, log1p() returns NaN and may set errno to EDOM.
     If x is less than -1.0, log1p() returns -HUGEVAL or NaN and sets
     errno to EDOM. If x is -1.0, log1p() returns -HUGEVAL and may set
     errno to ERANGE.

     pow() and powf() return 0 and set errno to EDOM when x is 0 and y is
     non-positive, or when x is negative and y is not an integer. In these
     cases, a message indicating DOMAIN error is output on standard error.
     When the correct value for pow() or powf() would overflow or under-
     flow, these functions return HUGEVAL or 0, respectively, and set
     errno to ERANGE.

     sqrt() and sqrtf() return 0 and set errno to EDOM when x is negative,
     and a message indicating DOMAIN error is output on standard error.





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exp(3M)                                                             exp(3M)

NOTES
     The functions sinhf(), coshf(), and tanhf() can be used in ANSI mode
     only.

SEE ALSO
     ilogb(3C), isnan(3C), hypot(3M), matherr(3M), sinh(3M), math(5).
















































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