# MATLAB: I’m getting wrong answer

arraysintegration

I'm trying to calculate the volume under x^2+ 1 curve when the curve is rotated around the x axis.This integration is from 0 to 3 with x incrementing by 0.1 using disk method.I did is the following way: l = 0.1;
sum = 0
for index = 1:30;
x = (index-1)*0.1;
y = pi*((x^2+1)^2)*l;
sum = sum + y;
end
clc; I'm getting volume 203.418093.However, the calculator integration gives volume 218.6548.