1/*
2 Copyright(C) 2003
3 All Rights Reserved. Salih Yurttas, ZCubes, BitsOfCode Software Systems, Inc..
4
5 Permission to use, copy, modify, and distribute this
6 software and its documentation for EDUCATIONAL purposes
7 and without fee is hereby granted provided that this
8 copyright notice appears in all copies.
9
10 date : September 1, 2003.
11 author : Salih Yurttas.
12
13 purpose : integration of f(x) = x*x;
14
15 integrate.cpp
16*/
17
18
19double fx(double x) {
20 return x * x;
21}
22
23double integrate(const double a,
24 const double b) {
25
26// evaluates approximately the integral of F(x)
27// between limits a and b,
28// using the trapezoidal rule with 8 intervals
29
30 int n = 8;
31
32 double w,
33 sum;
34
35 w = (b-a) / (double) n;
36
37 sum = (fx(a) + fx(b)) / 2.0;
38
39 for(int i=1; i<n; i++)
40 sum += fx((a + (double) i * w));
41
42 return w*sum;
43
44}