Lines Matching defs:acos
839 /* acos(x)
841 * acos(x) = pi/2 - asin(x)
842 * acos(-x) = pi/2 + asin(x)
844 * acos(x) = pi/2 - (x + x*x^2*R(x^2)) (see asin.c)
846 * acos(x) = pi/2 - (pi/2 - 2asin(sqrt((1-x)/2)))
853 * acos(x) = pi - 2asin(sqrt((1-|x|)/2))
862 double acos(double x) {
888 return 0.0; /* acos(1) = 0 */
890 return pi + 2.0 * pio2_lo; /* acos(-1)= pi */
892 return std::numeric_limits<double>::signaling_NaN(); // acos(|x|>1) is NaN