I am having problems in Numerical Methods with Simpson's 3/8 rule of integration. Of course, this is computer driven. The code that I have written for Matlab (SV7) goes as such:(adsbygoogle = window.adsbygoogle || []).push({});

1) function simpson38(f,n,a,b)

2) h = (b-a)/n;

3) x = a;

4) sum = f(x);

5) for i = 1:3:(n-3)

6) x = x + h;

7) sum = sum + 3 * f(x);

8) x = x + h;

9) sum = sum + 3 * f(x);

10) x = x + h

11) sum = sum + 2* f(x);

12) end

13) x = x + h;

14) sum = sum + 3 * f(x);

15) x = x + h;

16) sum = sum + 3 * f(x);

17) x = x + h

18) sum = sum + f(b);

19) I = (b-a) * sum/(8*n)

f = the function to be integrated, n = number of points, h = the stepsize, i is a counter, and sum is the sum of the values. a and b are the endpoints. I = the final integrated value.

If I am reading the book right, the middle points are given a weight of 3/8 each, with the end points given a weight of 1/8. With that in mind, line 11 should be weighted 2/8 (end point from 2 directions) unless it is the final endpoint.

What am I missing?

Thanks

Bill

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# Homework Help: Simpson's 3/8's rule

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