CEXP(3)                FreeBSD Library Functions Manual                CEXP(3)

NAME
     cexp, cexpf, cexpl - complex exponential functions

LIBRARY
     Math Library (libm, -lm)

SYNOPSIS
     #include <complex.h>

     double complex
     cexp(double complex z);

     float complex
     cexpf(float complex z);

     long double complex
     cexpl(long double complex z);

DESCRIPTION
     The cexp(), cexpf(), and cexpl() 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(), cexpf(), and cexpl() functions conform to ISO/IEC 9899:1999
     ("ISO C99").

FreeBSD 13.1-RELEASE-p6        November 3, 2021        FreeBSD 13.1-RELEASE-p6