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:

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

EXAMPLE

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

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

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

SEE ALSO

cabs(3), carg(3), cexp(3), cimag(3), creal(3)