newton method and secant method

newton-method.clj

(defn newt [x0 f df n] (take n (iterate #(- % (double (/ (f %) (df %)))) x0)))

;;call it like this:
;;(newt 1 #(- (* % %)  2.0) #(* 2.0 %) 10.0)

;; secant method
(defn secant
  [x0 x1 f n]
  (letfn [(fn_ [x_n-1 x_n-2 f_]
            (let [x_n (- x_n-1 (/ (* (f_ x_n-1) (- x_n-1 x_n-2)) 
                                (- (f_ x_n-1) (f_ x_n-2))))]
            [x_n x_n-1 f_]))]
    (take n (map first (iterate #(apply fn_ %) [x0 x1 f])))))