up vote 1 down vote. 2D cross products are more properly called 2d wedge products. Wedge products generalize to other dimensions, but cross products are always 3d wedge products. The usual operator symbol for a wedge product is ^ . You can use 2d wedge products to determine if one vector is to the left or the right of another one. If vector A is to the right of vector B, then, if A is to the left. If they are parallel or either of them is 0, then A ^ B = 0. In vector graphics, 2d wedge products can be used to analyze the intersection of 2 parametrized curves, e.g. for removing portions of one curve that lies to the right of another.
Definition of morning star for Students. : a bright planet (as Venus) seen in the eastern sky before or at sunrise.
Both Mercury and Venus are both evening and morning stars. That is because they are nearer to the sun than the earth is, so they can never appear very far from the sun in the sky. In other words, when the sun sets in the evening they might be in the west, near the sun as an evening star.