SICP in Clojure: Chapter 1, Exercise 40

This is my Clojure solution to Chapter 1, Exercise 40:

(ns sicp.ch1.ex40
  (:require [sicp.ch1.ex15 :as ch1-ex15]
            [sicp.ch1.ex16 :as ch1-ex16]
            [sicp.ch1.ex35 :as ch1-ex35]))

(def dx 0.00001)

(defn deriv
  [f]
  #(/ (- (f (+ % dx)) (f %)) dx))

(defn newton-transform
  [f]
  #(- % (/ (f %) ((deriv f) %))))

(defn newtons-method
  [f guess]
  (ch1-ex35/fixed-point (newton-transform f) guess))

(defn cubic
  [a b c]
  #(+ (ch1-ex15/cube %)
      (* a (ch1-ex16/square %) (* b %) c)))

(comment
  (< ((cubic 1 2 3) (newtons-method (cubic 1 2 3) 1.0)) dx)
  #__)