Secant method error, "subscript indicies must be real or positive integers"

here is my code, I get the error at line 10 at x(n+1) = x(n) - .... I have also attached it as an .m file

Matlab code
y = @(x) x.^3 - .3;
x(1) = .01;
x(2) = .02;
tol = 1e-5;
eps = 500;
iteration_secant = 0;
n = 1;
while abs(eps) > tol
x(n+1) = x(n) - ((y(x(n))*(x(n)-x(n-1))/(y(x(n))-y(x(n-1)))));
  iteration_secant = iteration_secant +1; 
  eps = ((x(n+1) - x(n))/x(n));
  n=n+1;
  if n > 100
      break
  end
end
x(n+1)

Answer 1

[Roger Stafford]

You enter the while loop with n = 1. This means that x(n-1) would have an index value of zero. This is a no-no in Matlab. You will have to revise your code to avoid this.

[Harjot Purewal]

I have changed it to n=2; from n=1; however I still get the same error and for some reason the value of n is still 1 when I run my code any idea of why this is the case?