29 lines
598 B
C++
29 lines
598 B
C++
#include<iostream>
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using namespace std;
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double arctan(double x);
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int main(int argc, char const *argv[])
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{
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double a = 16.0*arctan(1.0/5.0);
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double b = 4.0*arctan(1.0/239.0);
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double pi = a-b;
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cout<<pi<<endl;
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system("pause");
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return 0;
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}
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double arctan(double x)
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{
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double head=x;
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int tail=1;
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double art=0;
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while(double(head/tail)>1e-15)
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{
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art=(tail%4==1)? art+head/tail: art-head/tail;
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head*=x*x;
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tail+=2;
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cout<<"---------------"<<endl;
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cout<<tail<<endl;
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cout<<"---------------"<<endl;
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}
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return art;
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}
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