Eval and derive polynomials

poly.clj

(defn accumulate [op initial sequence]
  (if (empty? sequence)
    initial
    (op (first sequence)
        (accumulate op initial (rest sequence)))))

(defn eval-poly [x coefs]
  (accumulate (fn [c0 cs]
                (+ c0 (* x cs)))
              0
              coefs))

(defn d-poly [coefs]
  (let [pos (range (count coefs))]
    (rest (map (fn [[a b]] (* a b)) (map vector pos coefs)))))

(eval-poly 4
           (d-poly
            (d-poly (list 0 65 (/ 18 (Math/sqrt 4)) (/ 3 (Math/sqrt 36))))))
; # => 30.0