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public static void main(String[] args) {
	double z = 0.577350269189626; //alpha = 30°
	double sum = 0;
	for (int n = 0; n < 100; n++) {
		double prod = 1;
		int k = 1;
		while (k <= n) {
			prod *= 2*k*z*z/((2*k+1)*(1+z*z));
			k++;
		}
		sum += prod;
	}
	double alpha = z/(1+z*z) * sum;
	System.out.println(alpha * 180/Math.PI);
}