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  1. #include <iostream>
  2. #include <iomanip>
  3. #include <cmath>
  4.  
  5. using namespace std;
  6.  
  7. double pi = 3.14159265358;
  8.  
  9. double Paul(double x, double eps)
  10. {
  11.     double y = 1, summa = 0, last = 1;;
  12.     for (; fabs(last) > eps;)
  13.     {
  14.         last = pow(-1, y) * pow(x, 2 * y - 1) / (2 * y - 1);
  15.         summa += last;
  16.         y+=1;
  17.     }
  18.     return pi/2 + summa;
  19. }
  20.  
  21. double Harry(double x, double eps)
  22. {
  23.     double summ = pi/2 - x, x2n_1 = -x;
  24.     x *= x;
  25.  
  26.     for(int k = 3; fabs(x2n_1/k) > eps; k += 2)
  27.     {
  28.         x2n_1 *= -x;
  29.         summ += x2n_1/k;
  30.     }
  31.     return summ;
  32. }
  33.  
  34. int main()
  35. {
  36.     for(double x = 0; x <= 0.9; x += 0.1)
  37.     {
  38.         cout << setw(4) << x
  39.             << setw(12) << pi/2-atan(x)
  40.             << setw(12) << Paul(x, 1e-10)
  41.             << setw(12) << Harry(x, 1e-10) << endl;
  42.     }
  43.  
  44.  
  45. }
  46.  
Success #stdin #stdout 0s 4476KB
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stdin
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Standard input is empty
stdout
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   0      1.5708      1.5708      1.5708
 0.1     1.47113     1.47113     1.47113
 0.2      1.3734      1.3734      1.3734
 0.3     1.27934     1.27934     1.27934
 0.4     1.19029     1.19029     1.19029
 0.5     1.10715     1.10715     1.10715
 0.6     1.03038     1.03038     1.03038
 0.7     0.96007     0.96007     0.96007
 0.8    0.896055    0.896055    0.896055
 0.9    0.837981    0.837981    0.837981
https://ideone.com/7aZCr9
language:
C++14 (gcc 8.3)
created:
5 years ago
visibility:
public

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