1 /* origin: OpenBSD /usr/src/lib/libm/src/s_cacos.c */
3 * Copyright (c) 2008 Stephen L. Moshier <steve@moshier.net>
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
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9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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18 * Complex circular arc cosine
23 * double complex cacos();
24 * double complex z, w;
32 * w = arccos z = PI/2 - arcsin z.
38 * arithmetic domain # trials peak rms
39 * DEC -10,+10 5200 1.6e-15 2.8e-16
40 * IEEE -10,+10 30000 1.8e-14 2.2e-15
45 double complex cacos(double complex z)
50 w = (M_PI_2 - creal(w)) - cimag(w) * I;