# trepezidal

Feb 12th, 2024
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1. #include <bits/stdc++.h>
2. using namespace std;
3.
4. // Function to integrate
5. double f(double x) {
6.     return x * x * x; // Example function x^2
7. }
8.
9. // Trapezoidal rule function
10. double trapezoidal(double a, double b, int n) {
11.     double h = (b - a) / n; // Width of each trapezoid
12.     double sum = 0.5 * (f(a) + f(b)); // Sum of the first and last terms
13.
14.     for (int i = 1; i < n; ++i) {
15.         double x = a + i * h; // Current x value
16.         sum = sum + f(x); // Add f(x_i)
17.     }
18.
19.     return sum * h;
20. }
21.
22. int main() {
23.     double a, b; // Integration limits
24.     int n; // Number of subdivisions
25.
26.     // Input values
27.     cout << "Enter lower limit of integration: ";
28.     cin >> a;
29.     cout << "Enter upper limit of integration: ";
30.     cin >> b;
31.     cout << "Enter the number of subdivisions: ";
32.     cin >> n;
33.
34.     // Calculate integral using trapezoidal rule
35.     double integral = trapezoidal(a, b, n);
36.
37.     // Output result
38.     cout << "Approximate integral: " << integral << endl;
39.
40.     return 0;
41. }
42.