(define (cube x) (* x x x))

(define (p x) (- (* 3 x) (* 4 (cube x))))

(define (sine angle)
  (if (< (abs angle) 0.1)
      angle
      (p (sine (/ angle 3.0)))))

; (sine 12.15)
; (p (sine 4.05))
; (p (p (sine 1.35)))
; (p (p (p (sine 0.45))))
; (p (p (p (p (sine 0.15)))))
; (p (p (p (p (sine 0.05)))))
; (p (p (p (p 0.05))))
; ...
; => p is applied four times

; (sin a)
; linear recursive process
; O(log(a)) time and space complexity
; ~log(a/0.1)/log(3) steps