The opposite vector of vector A is noted - A . Then the vector Q is defined as r times the vector P . Orthogonal projection Take an x-axis with origin in O and any vector P . Say P' is the orthogonal projection of P on x. Then vector P ' is called the vector-projection of P on x.
Definition Let x be an axis with P on x.
The dot product of two vectors P and Q is defined by P . It can be proved that P . P For any vector U , V and W U . The dot product of two vectors is distributive with respect to the addition of vectors. Let E and U be two unity vectors.