freebsd man page for cexp

CEXP(3) 						   BSD Library Functions Manual 						   CEXP(3)

NAME
     cexp, cexpf -- complex exponential functions

LIBRARY
     Math Library (libm, -lm)

SYNOPSIS
     #include <complex.h>

     double complex
     cexp(double complex z);

     float complex
     cexpf(float complex z);

DESCRIPTION
     The cexp() and cexpf() functions compute the complex exponential of z, also known as cis(z).

RETURN VALUES
     For real numbers x and y, cexp() behaves according to Euler's formula:

	   cexp(x + I*y) = (e**x * cos(y)) + (I * e**x * sin(y))

     Generally speaking, infinities, zeroes and NaNs are handled as would be expected from this identity given the usual rules of floating-point
     arithmetic.  However, care is taken to avoid generating NaNs when they are not deserved.  For example, mathematically we expect that
     cimag(cexp(x + I*0)) = 0 regardless of the value of x, and cexp() preserves this identity even if x is infinity or NaN.  Likewise,
     cexp(-infinity + I*y) = 0 and creal(cexp(infinity + I*y)) = infinity for any y (even though the latter property is only mathematically true
     for representable y.)  If y is not finite, the sign of the result is indeterminate.

SEE ALSO
     complex(3), exp(3), math(3)

STANDARDS
     The cexp() and cexpf() functions conform to ISO/IEC 9899:1999 (``ISO C99'').

BSD
								   March 6, 2011							       BSD