Calculation dihedral angle from 2 vectors
計算acos的簡單範例，先用以下公式求出cos值，再利用acos得到角度
/* acos example */ #include <stdio.h> #include <math.h> #define PI 3.14159265 int main () { double param, result; param = 0.5; result = acos (param) * 180.0 / PI; printf ("The arc cosine of %lf is %lf degrees.\n", param, result ); return 0; }
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