(DEFUN F (X)
 ((- (SIN X) (* (/ D C) X))
)
(DEFUN F2 (X)
  (- (COS X) (/ D C)
)
(DEFUN C:ARC-EEL (/ A B C D Z)
  (SETQ A (GETPOINT "1st Point: "))
  (SETQ B (GETPOINT "\n2ND Point: "))
  (SETQ C (GETREAL "\nArc length: "))
  (SETQ D (DISTANCE A B))
  (SETQ Z (/ PI 2.0))
  (WHILE (> (ABS (/ (F Z)(SIN Z)))
      0.005)
    (SETQ Z (- Z (/ (F Z) (F2 Z))))
    (IF (> Z PI)
      (SETQ Z 3.14)
    )
  (
  (SETQ Z (/ (* Z 360.0) PI))
  (COMMAND "ARC" A "E" B "A" Z)
)