Multiplying a vector and a scalar s\mathtt a = (sa_x,sa_y,sa_z) does not change the direction of the vector, only the length. Addition and subtraction of vectors\mathtt a+\mathtt b = [(a_x+b_x),(a_y+b_y),(a_z+b_z)] Superimpose the two offsets, similar to the resultant force of the force. \mathtt a-\mathtt b = [(a_x-b_x),(a_y-b_y),(a_z-b_z)] is equivalent to adding the opposite of another vector. direction + direction = direction direction – direction = direction point + direction = point point –