#| BEGIN (Write your solution here) |#
(define (cont-frac n d k)
  (define (f c)
    (if (> c k)
        0
        (/ (n c) (+ (d c) (f (+ c 1))))))
  (f 1))

(define (e k)
  (let ((n (lambda (k) 1.0))
        (d (lambda (k) (if (= (modulo (+ k 1) 3) 0)
                           (* 2 (/ (+ k 1) 3))
                           1))))
  (+ (cont-frac n d k) 2.0)))
#| END |#