Numerical calculation, using trapezoidal method and Parabola method to calculate pi

Formula pai=4*∫10dx/(1+X2)

The [0.1] is divided into 10 equal parts, which are calculated separately by two methods.

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Class Work2 {public static void main (String args[]) {Double h = 0.1;//parameter H double m1 = 0;//complex trapezoid sum sum double n = 10;   Double i=0;//final result double h_2 = 0.2; Double m = 5;//Because of n=2m.n=10, so m=5 double s1=0;//parabolic first array summation double s2=0;//complex parabola second array summation double ss[] = new DOUBLE[10] The sum element in the calculation of the trapezoid formula double ss1[]=new The first array used in the double[5];//parabolic line double ss2[]=new double[4];//second array used in the complex parabola

Double K[]={0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9};//10 [0,1] for (int i=0;i<10;i++) {Ss[i] = 1/(1+k[i]*k[i));     }//teat pass for (int i =0;i<10;i++) {m1 = M1 +ss[i]; //test Pass I = h_2* (0.5+2*M1);//0.5 is f (b)

--------------------Test Code System.out.println ("= = = Complex Trapezoid formula calculation (including test and results) = =");     System.out.println ("The single result of the complex trapezoid formula"); for (int i =0;i<10;i++) {System.out.println (ss[i]);

    }     System.out.println ("Result sum M is" + M1);     SYSTEM.OUT.PRINTLN ("The result is" + I);     System.out.println ("=================================="); / ------------------------------------------------    //== start the complex parabolic formula calculation ======      System.out.println ("Complex parabola formula calculation");    //Because the operation of the array of parabolic operations is more complex, I redefine arrays k[]      double k_2[] = {0,0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9};    // So the array k corresponds to the actual, oh haha           for (int i =1;i<=m;i++) {       int n1 = 2*i-1;      ss1[i-1] = 1/(1+K_2[N1]*K_2[N1));     & nbsp;      system.out.println (ss1[i-1])//test calculation is correct,    }      System.out.println ("correct operation");     System.out.println ("second array calculation"); &NBSP;&NBsp;   for (int i = 1;i<= (m-1), i++) {      int n1 = 2*i;     & NBSP;SS2[I-1]=1/(1+k_2[n1]*k_2[n1]);      system.out.println (ss2[i-1));//test calculation is correct,     }     System.out.println ("correct operation");    //sum of 2 arrays      for (int i =0;i<5;i++) {        S1 = S1 +ss1[i];      }     System.out.println ("Ss1 sum is" + S1);     for ( int i =0;i<4;i++) {        s2 = s2 +ss2[i];     }      System.out.println ("Ss2 sum is" + s2);     System.out.println ("correct operation");      i = (H/3) * (1+0.5+4*S1+2*S2);     System.out.println ("result is" + i);     //Parabolic method do not know is not correct, the book has no answer          } &nbsP } ===========================================