can someone explain me this code please?

clc;
clear all;
close all;

f=@(x)x.^3; 
a=1;b=2; 
n=1.25; 
h=(b-a)/n;
p=0;

for i=a:b
p=p+1;
x(p)=i;
y(p)=i.^3; 
end

l=length(x);
x
y
answer=(h/2)*((y(1)+y(l))+2*(sum(y)-y(1)-y(l)))

Answer 1

[Roger Stafford]

This looks like a misguided attempt to use trapezoidal approximation to find the integral of y = x^3 over an interval in x. The values assigned to 'a', 'b', and 'h' are inappropriate for such an interpretation however.

Anyhow, there is a much easier method for such an integral using calculus:

 answer = (b^4-a^4)/4;

Why do numerical approximation when such an easy formula exists with the exact answer?