1 .\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
2 .\" Distributed under GPL
4 .TH COMPLEX 7 2009-07-25 "" "Linux Programmer's Manual"
6 complex \- basics of complex mathematics
8 .B #include <complex.h>
10 Complex numbers are numbers of the form z = a+b*i, where a and b are
11 real numbers and i = sqrt(\-1), so that i*i = \-1.
13 There are other ways to represent that number.
14 The pair (a,b) of real
15 numbers may be viewed as a point in the plane, given by X- and
17 This same point may also be described by giving
18 the pair of real numbers (r,phi), where r is the distance to the origin O,
19 and phi the angle between the X-axis and the line Oz.
21 z = r*exp(i*phi) = r*(cos(phi)+i*sin(phi)).
23 The basic operations are defined on z = a+b*i and w = c+d*i as:
25 .B addition: z+w = (a+c) + (b+d)*i
27 .B multiplication: z*w = (a*c \- b*d) + (a*d + b*c)*i
29 .B division: z/w = ((a*c + b*d)/(c*c + d*d)) + ((b*c \- a*d)/(c*c + d*d))*i
31 Nearly all math function have a complex counterpart but there are
32 some complex-only functions.
34 Your C-compiler can work with complex numbers if it supports the C99 standard.
36 The imaginary unit is represented by I.
39 /* check that exp(i * pi) == \-1 */
40 #include <math.h> /* for atan */
47 double pi = 4 * atan(1.0);
48 double complex z = cexp(I * pi);
49 printf("%f + %f * i\\n", creal(z), cimag(z));