(defun c:slope( / )
  (setq p1 (getpoint "pick the 1st point: "))
  (setq p2 (getpoint p1 "pick the 2nd point: "))
  (setq SL2 (getreal "input slope= "))

  (setq t1 (angle p1 p2))
  (setq s2 (distance p1 p2))

  (if (> (abs SL2) 0.0)
    (setq dt (atan (/ 1.0 sl2)))
    (setq dt 0.0))

  (setq t2 (+ t1 dt))
  (setq p2 (polar p1 t2 s2))
  (command "line" p1 p2 "")
  (princ)
  ); end of slope

(princ "do the command of SLOPE")
(princ)