1ATAN(3) Linux Programmer's Manual ATAN(3)
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6 atan, atanf, atanl - arc tangent function
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9 #include <math.h>
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11 double atan(double x);
12 float atanf(float x);
13 long double atanl( long double x);
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15 Link with -lm.
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18 The atan() function calculates the arc tangent of x; that is the value
19 whose tangent is x.
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22 The atan() function returns the arc tangent in radians and the value is
23 mathematically defined to be between -PI/2 and PI/2 (inclusive).
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26 SVr4, POSIX.1-2001, 4.3BSD, C89. The float and long double variants
27 are C99 requirements.
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30 acos(3), asin(3), atan2(3), carg(3), catan(3), cos(3), sin(3), tan(3)
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34 2002-07-27 ATAN(3)