Manpages - catan.3

catan, catanf, catanl - complex arc tangents

  #include <complex.h>

  double complex catan(double complex z);
  float complex catanf(float complex z);
  long double complex catanl(long double complex z);

  Link with -lm.

These functions calculate the complex arc tangent of z. If y = catan(z), then z = ctan(y). The real part of y is chosen in the interval [-pi/2,pi/2].

One has:

      catan(z) = (clog(1 + i * z) - clog(1 - i * z)) / (2 * i)

These functions first appeared in glibc in version 2.1.

For an explanation of the terms used in this section, see *attributes*(7).

C99, POSIX.1-2001, POSIX.1-2008.

  /* Link with "-lm" */

  #include <complex.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <stdio.h>

  int
  main(int argc, char *argv[])
  {
      double complex z, c, f;
      double complex i = I;

      if (argc != 3) {
          fprintf(stderr, "Usage: %s <real> <imag>\n", argv[0]);
          exit(EXIT_FAILURE);
      }

      z = atof(argv[1]) + atof(argv[2]) * I;

      c = catan(z);
      printf("catan() = %6.3f %6.3f*i\n", creal(c), cimag(c));

      f = (clog(1 + i * z) - clog(1 - i * z)) / (2 * i);
      printf("formula = %6.3f %6.3f*i\n", creal(f2), cimag(f2));

      exit(EXIT_SUCCESS);
  }

*ccos*(3), *clog*(3), *ctan*(3), *complex*(7)

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