MATLAB: Integrating using sums(riemann sums)

MATLABriemann sum

Hi, i want to find the integral of function f without using the int function with the limits 5 and 17 . I want to find the riemann sum of the function f.

I tried solving it by using the int function but now i want to find the area withou using int. below is my code but n should represent the number of divisions that gives an accuracy of 10^-4 , i am not sure if my value of n is correct or not? how do i find n and the area (c) ?please help.

format longG
syms x
f = 2*pi*(0.16*(0.25-(x-1)^2)+44.52)*(1+(-0.32*x - 0.32)^2)^1/2;
a = int(f,5,17.688);
b = sym(a);
c = double(b);
n = (17.688-5)/0.0001;
SurfaceArea = [c n]

Best Answer

You may use rsums. It allows you to interactively calculate the riemann sum integral:

rsums(f,5,17.688)

Riemann Sum Integral

Related Solutions

MATLAB: Determining the number of divisions in riemann sums

You did not say if you wanted left, right, middle riemann sum. This is left.

f = @(x)2*pi*(0.16*(0.25-(x-1).^2)+44.52).*(1+(-0.32*x - 0.32).^2).^1/2;
a=1;%whatever bounds you want

b=3;%whatever bounds you want
Rs(1) = f(a)*(b-a);
Rs(2) = sum(f(linspace(a,b,2)).*((b-a)/2));
n=2;
while abs(Rs(n)-Rs(n-1))>1e-5
    n=n+1;
    Rs(n) = sum(f(linspace(a,b,n)).*((b-a)/n));
end

MATLAB: Can someone check the for loop

You need to sum ‘l’ (lower case ‘L’). Then it works.

Doing that, I got your professor’s answer for ‘sin(x)’ but not for ‘x^2’. I suspect that with your same code giving the correct answer for one and the incorrect answer for the other, one of your professor’s answers is incorrect.

Best Answer

Related Solutions

MATLAB: Determining the number of divisions in riemann sums

MATLAB: Can someone check the for loop

Related Question