Help storing data from while loop

I am working on an assignment where I need to save the iteration and the root value for each iteration under a single column matrix I am going to put my code underneath. Please let me know if you can help!

x = [0:0.1:2];
% Set bounds for graph
F = 5*sin(x/4)-1.3;
% Create function for graph
plot(x,F),grid
% Display function
[bracket,x] = ginput(2)
% Let user select two bounds from graph
x_lo = min(bracket)
x_up = max(bracket)

f = @(x) 5*sin(x/4) - 1.3 
error = 10;
iter = 0
while error > 1e-4
    iter = iter+1
    tr = x_lo - f(x_lo)*(x_up-x_lo)/(f(x_up) - f(x_lo))
    fr = f(tr)
    if sign(fr) == sign(f(x_up))
        x_up = tr
        
    else
        x_lo = tr
        
    end 
    error = abs(fr);
    
end
root = tr

Answer 1

[Walter Roberson]

info_to_save(iter, :) = [iter, fr];

However, since you know that the iterations always increase by 1 each time, you do not need to store the iteration number:

info_to_save(iter) = fr;

And afterwards:

[(1:length(info_to_save)).', info_to_save(:)]