Load up Matlab and paste in the following code:
%% Find the zeros of the Bessel Function
alpha = 2.4;
beta = 8.65;
%% Other Parameters
aa = 1; % what is the length
order = 0; % What order of Bessel
rr = linspace (0,aa,10000); % define values of rr from 0 to aa
JPa = besselj(order,alpha*rr); % Use Matlab built in function for
JPb = besselj(order,beta*rr); % Bessel functions
%% Intgrate over the r J_p(alpha r / aa) J_p(beta r /aa ) from 0 to aa
Meaty = rr .* JPa .* JPb; % Get the middle inside
Value = trapz(rr, Meaty); % Do the integral
titleStr = sprintf ('Integral Value = %f', Value);
%% Plot results
plot (rr, JPa, '-k', 'linewidth', 2)
hold on
plot (rr, JPb, '-b', 'linewidth', 2)
hold off
xlabel ('rr');
ylabel ('Bessel');
title (titleStr); %Output the results of the intgral
legend ('alpha', 'beta')
Answer the following questions:
- What is the value of J0(alpha aa / aa) = J0(alpha) = J0(2.4)?
- What is the value of J0(beta aa / aa) = J0(beta) = J0(8.65)?
- What is the result of the following integral?

- In the code, alpha = 2.4 and beta = 8.65. This is the first and third zero for the p=0 Bessel function. Can you please find the second and the fourth?
- Can you please fill in the values for the integral for this table? In the box put in the value of the integral?
| beta down alpha -> | 2.4 | ?? | 8.65 | ?? |
| 2.4 | ||||
| ?? | ||||
| 8.65 | ||||
| ?? |
- Review the notes from class. Develop at least three questions: Class Notes: https://cosmicpathways.org/wp-content/uploads/2021/04/besselorthogonalityproof.pdf
- Write a paragraph discussing how the analytical solution for this integral, shown below, matches the results in the table.

- Write a paragraph discussing how you would find the table for the J1 case.
