pendOde :: Floating a => PendX a -> PendP a -> a -> PendX a
pendOde (PendX theta omega) (PendP mass) t = PendX omega ((9.8 * sin theta + force) / mass)
  where
    force = 0.3 * sin t
pendOde :: Floating a => PendX a -> PendP a -> a -> PendX a
pendOde (PendX theta omega) (PendP mass) t = PendX omega ((9.8 * sin theta + force) / mass)
  where
    force = 0.3 * sin t
pendOde (PendX theta omega) (PendP mass) t = PendX omega ((9.8 * sin theta + force) / mass)
  where
    force = 0.3 * sin t