amath  1.8.5
Simple command line calculator
vcs.c
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1 /*-
2  * Copyright (c) 2014-2018 Carsten Sonne Larsen <cs@innolan.net>
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29 
30 /**
31  * @file vcs.c
32  * @brief Versed cosine function
33  */
34 
35 #include "prim.h"
36 
37 /**
38  * @brief Versed cosine function
39  * @details
40  * <pre>
41  * vercos = 1+cos(x)
42  * = 2*cos(x/2)*cos(x/2)
43  * </pre>
44  */
45 double vcs(double x)
46 {
47  double a = x / 2.0;
48  double b = cos(a);
49  double c = 2 * b * b;
50  return c;
51 }
double cos(double x)
Cosine function.
Definition: cos.c:87
double vcs(double x)
Versed cosine function.
Definition: vcs.c:45