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  1.  
  2. #include <stdio.h>
  3. #include <stdlib.h>
  4. #include <locale.h>
  5. #include <math.h>
  6. #define PI 3.14159
  7.  
  8.  
  9. double formula (double x) {
  10.     return (pow(x, 3)* cos(3*PI*x)*exp(x)-pow(x,2)*cos(2*PI*x)*exp(0.5*x)+5);
  11. }
  12.  
  13. double der2 (double x) {
  14.     return -9*pow(PI,2)*exp(x)*pow(x,3)*cos(3*PI*x)-0.25 * exp(0.5*x)*pow(x, 2)*cos(2*PI*x)-exp(0.5*x)*(-4*pow(PI,2)*pow(x,2)*cos(2*PI*x)-8*PI*x*sin(2*PI*x)+2*cos(2*PI*x))-exp(0.5*x)*(2*x*cos(2*PI*x)-2*PI*x*x*sin(2*PI*x))-6*PI*(exp(x)*pow(x,3)+3*exp(x)*pow(x,2))*sin(3*PI*x)+(exp(x)*pow(x,3)+6*exp(x)*pow(x,2)+6*exp(x)*x)*cos(3*PI*x);
  15. }
  16.  
  17. double halfDiv (double a, double b) {
  18.     double x = (a + b) / 2;
  19.     while (abs(b - a) > 0.00001) {
  20.         if (formula(b)*formula(x)<0) a = x;
  21.         else b = x;
  22.         x = (a + b)/2;
  23.     }
  24.     return x;
  25. }
  26.  
  27. double horda(double a, double b){
  28.     double c;
  29.     while (abs(formula(b) - formula(a)) > 0.00001)
  30.     {
  31.         c = (formula(b)*a - formula(a)*b)/(formula(b)-formula(a));
  32.         if ((formula(a)*formula(c))>0) a=c;
  33.         else b = c;
  34.     }
  35.     return b;
  36. }
  37.  
  38. double touch (double a, double b) {
  39.     double c = (formula(a)*der2(a)>0) ? a : b;
  40.     double fc;
  41.     double fder2;
  42.     double d = 0;
  43.     do {
  44.         d += c;
  45.         fc = formula(c);
  46.         fder2 = der2(c);
  47.         c -= fc/fder2;
  48.         d -= c;
  49.         d = abs(d);
  50.     } while (d > 0.00001);
  51.     return c;
  52. }
  53.  
  54. int main()
  55. {
  56.     double x1, x2;
  57.     setlocale(LC_ALL, "rus");
  58.     printf("Введите через пробел концы отрезка (a и b соответственно): ");
  59.     scanf("%lf %lf", &x1, &x2);
  60.     if (formula(x1)*formula(x2)>0) printf("Невалидный интервал!");
  61.     else printf("Решение методом деления пополам:\nx = %lf\nf(x) = %lf\n\nРешение методом хорд:\nx = %lf\nf(x) = %lf\n\nРешение методом касательных:\nx = %lf\nf(x) = %lf",halfDiv(x1, x2), formula(halfDiv(x1,x2)), horda(x1,x2), formula(horda(x1,x2)), touch(x1,x2), formula(touch(x1,x2)));
  62.     return 0;
  63. }
Success #stdin #stdout 0s 16880KB
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stdin
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Standard input is empty
stdout
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Введите через пробел концы отрезка (a и b соответственно): Невалидный интервал!
https://ideone.com/WQ5MnA
language:
C++14 (gcc 8.3)
created:
5 years ago
visibility:
public

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