1ACOS(3) Linux Programmer's Manual ACOS(3)
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6 acos, acosf, acosl - arc cosine function
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9 #include <math.h>
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11 double acos(double x);
12 float acosf(float x);
13 long double acosl(long double x);
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15 Link with -lm.
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18 The acos() function calculates the arc cosine of x; that is the value
19 whose cosine is x. If x falls outside the range -1 to 1, acos() fails
20 and errno is set.
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23 The acos() function returns the arc cosine in radians and the value is
24 mathematically defined to be between 0 and PI (inclusive).
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27 EDOM x is out of range.
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30 SVr4, POSIX.1-2001, 4.3BSD, C89, C99. The float and long double vari‐
31 ants are C99 requirements.
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34 asin(3), atan(3), atan2(3), cacos(3), cos(3), sin(3), tan(3)
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38 2004-10-06 ACOS(3)