- #include <iostream> 
- #include <cmath> 
- using namespace std; 
- int main(){ 
- 	double sum, eps, next, A; 
- 	int i=1; 
- 	eps=0.001; 
- 	A=-1/3.0; 
- 	sum=A; 
- 	while (abs(A)>eps){ 
- 		i=i+1; 
- 		sum=sum+A; 
- 		next=A*(-2)/(2*i+3); 
- 		A=next; 
- 	} 
-  	cout << "sum="<< sum << endl << "i=" << i << endl; 
-  	return 0; 
- } 
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