need help finding convergence

I have the following equation in matlab g1=@(x) tan(exp(x/20)) now I need to run this until I get two consecutive approximations to the root are close enough or divergence is determined. here is how i'm in iterating n=0; a=1; n=n+1; x1(n)=g1(a); a=x1(n); now this does work and I can run it, but i can't make the loop until i know how to find the error between xold and xnew. So my question is how to i make this so the equation is in the form xnew=g(xold)?

Answer 1

[Mischa Kim]

Tony, this should get you started:

 g      = @(x) tan(exp(x/20));
 my_tol = 1e-5;
 x      = 1;
 dx     = x;

 x_iter = x;
 while dx > my_tol
    x_new  = g(x);
    dx     = abs(x - x_new)
    x      = x_new;
    x_iter = [x_iter x];
 end

Answer 2

[Tony Montgomery]

Thank you. THANK you. THANK YOU!! I'm not very good at this stuff yet. Thanks for the help I will dry it!!