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The cross product A * B = ||A|| ||B|| sin q n where q is the angle,||A|| and ||B|| are the magnitudes of vectors A and B, and n is a unit vector perpendicular to the plane containing A and B in the direction given by the right-hand rule . If the vectors A and B are parallel (i.e., the angle ? between them is either 0° or 180°), by the above formula, the cross product of A and B is the zero vector 0.