Theorem 3.1 Let f : I ⊂ → for an open interval I and consider that the nonlinear equation f (x) = 0
(or x = g (x) ) has simple root α ∈ I , where g (x) : I ⊂ → be sufficiently smooth in the neighbourhood
of the root α . If 0 x is sufficiently close to α then iteration scheme defined by Algorithm 2.1 has at least
second order convergence.