How can i store absolute errors into a 1D array and then plot a e(k+1) against e(k)?

function Newton

% MATLAB M-file to solve a single equation using Newton's method.

% The function is f(x)= exp(x) - x - 2 = 0  

clc         % clear command window
clear       % clear workspace

        % Set the iteration number

x=input('Give the first starting value: ');% Set the starting value
k=0;
w=input('Give the final root for the first value: ');

diff = 1;   % Set the difference between successive x values
          % to an arbitrary value to start the iteration

while diff > 0.5e-5  % Continue until convergence is achieved to 5 decimal places

     xlast = x; 
     x = xlast - f(xlast)/fd(xlast);  %  defines x(k+1) = xk - f(xk)/f'(xk)

     diff = abs(x - xlast);  % Calculate the difference between two successive iterations

     ae=abs(x-w);

     k = k + 1;   % Add 1 to the iteration number
     fprintf('%15.8f\n', ae)  % Output the intermediate solutions to 6 decimal places
  end

function y = f(x)  %  Define f(x)
y = x.^3 -2.44*x.^2 - 8.9216*x + 22.1952;

function z = fd(x)  % Define f'(x)
z = 3*x^2 - 2*2.44*x - 8.9216;

[Stephen23]

@David Rogers: today I foramtted your code for you. In future you can do it yourself: select the code text, then click the {} Code button.

[Walter Roberson]

Using diff as a variable name interferes with using the MATLAB function diff()

Answer 1

[Walter Roberson]

ae(k) = abs(x-w);

After that you might want

plot(ae)

or

semilogy(ae)

or

plot(ae(2:end)./ae(1:end-1))