Error: Not Enough Input Arguments.

"Error using newton_mathod (line 48). Not enough input arguments" why does it give me this error message? here is my code:

function [ x, ex ] = newton_mathod(f,df,x0,tol,nmax)
syms x;
f=@(x)0.95*x^3 - 5.9*x^2 + 10.9*x - 6
df=@(x)2.85*x^2 - 11.8*x + 10.9
x0=1;
  if nargin == 3
      tol = 1e-4;
      nmax = 1e1;
  elseif nargin == 4
      nmax = 1e1;
  elseif nargin ~= 5
      disp('newton invalid input parameters');
  end

    f = inline('f');
    df = inline('df');
    x(1) = x0 - (f(x0)/df(x0));
    ex(1) = abs(x(1)-x0);
    k = 2;
    while (ex(k-1) >= tol) && (k <= nmax);
        x(k) = x(k-1) - (f(x(k-1))/df(x(k-1)));
        ex(k) = abs(x(k)-x(k-1));
        k = k+1;
    end
end

Answer 1

[Azzi Abdelmalek]

I don't know if you have done this code or find it somewhere. This code represent a function, but at the same time the input argument f and df are unnecessary, because they are defined inside your function

f=@(x)0.95*x^3 - 5.9*x^2 + 10.9*x - 6
df=@(x)2.85*x^2 - 11.8*x + 10.9

Then just after, they are replaced by

f = inline('f');
df = inline('df');