#include <iostream>
using namespace std;
 
long double f(long double s) //модуль числа
{
	if (s<0) s=-s;
	return s;
}
 
long double cotan (long double x, long double e)
{
	long double sin=x, cos=1, cotan=0, a=1;
	int n=2;
	while (f(cos/sin-cotan)>e)
	{ 
		cotan = cos/sin;
		a*=-x*x/((n-1)*n);
		cos+= a;
		sin+= a*x/(n+1);
		n+=2;
	}
	cotan = cos/sin;
	return cotan;
}
 
int main()
{
	long double x,e,c;
	cin>>x>>e;
	c = cotan(x,e);
	int n = 0;
	x = c;
	while (f(x)>e)
	{
		x = x/10;
		n++;
	}
	cout.precision(n);
	cout<<c;
	return 0;
}

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

MS42IDAuMDAwMDAx

1.6 0.000001