1ATAN2(3) Linux Programmer's Manual ATAN2(3)
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6 atan2, atan2f, atan2l - arc tangent function of two variables
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9 #include <math.h>
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11 double atan2(double y, double x);
12 float atan2f(float y, float x);
13 long double atan2l(long double y, long double x);
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15 Link with -lm.
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18 The atan2() function calculates the arc tangent of the two variables x
19 and y. It is similar to calculating the arc tangent of y / x, except
20 that the signs of both arguments are used to determine the quadrant of
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24 The atan2() function returns the result in radians, which is between
25 -PI and PI (inclusive).
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28 SVr4, POSIX.1-2001, 4.3BSD, C89. The float and long double variants
29 are C99 requirements.
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32 acos(3), asin(3), atan(3), cos(3), sin(3), tan(3)
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36 2002-07-27 ATAN2(3)