text: A point C on the screw axis satisfies the equation:
  Solve this equation for C using Cayley's formula for a rotation matrix
  where [B] is the skew-symmetric matrix constructed from Rodrigues' vector
  such that
  Use this form of the rotation A to obtain
  which becomes
  This equation can be solved for C on the screw axis P(t) to obtain,
  The screw axis  of this spatial displacement has the Plücker coordinates .