sin/cos series

main.cpp

#include <iostream>
#include <cmath>

int main(int argc, char** argv) {
	const size_t n = 10000000;
	double phi = 0.5;

	double cos1 = std::cos(phi);
	double sin1 = std::sin(phi);
	double cosi = cos1;
	double sini = sin1;
	for(std::size_t i = 2; i < n; ++i) {
//		double tmp = cos1*cosi - sin1*sini; // new cosi
//		sini       = sin1*cosi + cos1*sini;
//		cosi       = tmp;

		double sinc = std::sin(i*phi);
		double cosc = std::cos(i*phi);
		std::cout << i << " " << sinc << " " << cosc << std::endl;

	//	std::cout << i << " " << 2 * (sini-sinc) / (sini+sinc) << " " << 2 * (cosi-cosc) / (cosi+cosc) << std::endl;
	}

	return 0;
}