complex(7) — Linux manual page

complex(7)          Miscellaneous Information Manual          complex(7)

NAME

       complex - basics of complex mathematics

LIBRARY

       Math library (libm, -lm)

SYNOPSIS

       #include <complex.h>

DESCRIPTION

       Complex numbers are numbers of the form z = a+b*i, where a and b
       are real numbers and i = sqrt(-1), so that i*i = -1.

       There are other ways to represent that number.  The pair (a,b) of
       real numbers may be viewed as a point in the plane, given by X-
       and Y-coordinates.  This same point may also be described by
       giving the pair of real numbers (r,phi), where r is the distance
       to the origin O, and phi the angle between the X-axis and the
       line Oz.  Now z = r*exp(i*phi) = r*(cos(phi)+i*sin(phi)).

       The basic operations are defined on z = a+b*i and w = c+d*i as:

       addition: z+w = (a+c) + (b+d)*i

       multiplication: z*w = (a*c - b*d) + (a*d + b*c)*i

       division: z/w = ((a*c + b*d)/(c*c + d*d)) + ((b*c - a*d)/(c*c +
       d*d))*i

       Nearly all math function have a complex counterpart but there are
       some complex-only functions.

EXAMPLES

       Your C-compiler can work with complex numbers if it supports the
       C99 standard.  The imaginary unit is represented by I.

       /* check that exp(i * pi) == -1 */
       #include <math.h>        /* for atan */
       #include <stdio.h>
       #include <complex.h>

       int
       main(void)
       {
           double pi = 4 * atan(1.0);
           double complex z = cexp(I * pi);
           printf("%f + %f * i\n", creal(z), cimag(z));
       }

SEE ALSO

       cabs(3), cacos(3), cacosh(3), carg(3), casin(3), casinh(3),
       catan(3), catanh(3), ccos(3), ccosh(3), cerf(3), cexp(3),
       cexp2(3), cimag(3), clog(3), clog10(3), clog2(3), conj(3),
       cpow(3), cproj(3), creal(3), csin(3), csinh(3), csqrt(3),
       ctan(3), ctanh(3)

COLOPHON

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       part of the original manual page), send a mail to
       man-pages@man7.org

Linux man-pages 6.9.1          2024-06-15                     complex(7)

Pages that refer to this page: cabs(3), cacos(3), cacosh(3), carg(3), casin(3), casinh(3), catan(3), catanh(3), ccos(3), ccosh(3), cexp2(3), cexp(3), cimag(3), clog10(3), clog2(3), clog(3), conj(3), cpow(3), cproj(3), creal(3), csin(3), csinh(3), csqrt(3), ctan(3), ctanh(3)

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