>>699
こうなった

#include <iostream>
#include <boost/math/special_functions/sin_pi.hpp>
#include <boost/math/special_functions/cos_pi.hpp>

int main()
{
for (int i = 0; i <= 12; i++) {
double s = boost::math::sin_pi(i / 6.0);
double c = boost::math::cos_pi(i / 6.0);
printf("sin(%d/6π) = %19.16f cos(%d/6π) = %19.16f\n", i, s, i, c);
}
}

sin(0/6π) = 0.0000000000000000 cos(0/6π) = 1.0000000000000000
sin(1/6π) = 0.5000000000000000 cos(1/6π) = 0.8660254037844387
sin(2/6π) = 0.8660254037844386 cos(2/6π) = 0.5000000000000000
sin(3/6π) = 1.0000000000000000 cos(3/6π) = 0.0000000000000000
sin(4/6π) = 0.8660254037844387 cos(4/6π) = -0.4999999999999999
sin(5/6π) = 0.4999999999999999 cos(5/6π) = -0.8660254037844387
sin(6/6π) = -0.0000000000000000 cos(6/6π) = -1.0000000000000000
sin(7/6π) = -0.5000000000000002 cos(7/6π) = -0.8660254037844385
sin(8/6π) = -0.8660254037844385 cos(8/6π) = -0.5000000000000002
sin(9/6π) = -1.0000000000000000 cos(9/6π) = 0.0000000000000000
sin(10/6π) = -0.8660254037844385 cos(10/6π) = 0.5000000000000002
sin(11/6π) = -0.5000000000000002 cos(11/6π) = 0.8660254037844385
sin(12/6π) = 0.0000000000000000 cos(12/6π) = 1.0000000000000000