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C++ Programming/Code/Standard C Library/Functions/acos
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acos
#include <cmath>
double acos( double arg );
The acos() function returns the arc cosine of arg, which will be in the range [0, pi]. arg should be between -1 and 1. If arg is outside this range, acos() returns NAN and raises a floating-point exception.
Related topics asin - atan - atan2 - cos - cosh - sin - sinh - tan - tanh