def approx_first_derivative(fun, x, h):
    """
    Function to approximate the first derivative through central differences
        args:
            fun (function): function that will be approximated
            x (float): value where the function will be centered
            h (float): finite step that will be taken to evaluate de function
    """

    df = (fun(x + h) - fun(x - h))/(2*h)

    return df