扩(=x+y1j+1k =xi+vitek Then the displacement is =(x2-x1)i+(y2-y1)j+(z2-21k Direction: from start point to end point Magnitude: A-=VAx+Ay2+A222 2 2 Magnitude : r = x +y +z  Direction: from start point to end point if r x i y j z k     1 = 1 + 1 + 1 r x i y j z k     2 = 2 + 2 + 2 2 1 r r r     = − Then the displacement is x x i y y j z z k    ( ) ( ) ( ) = 2 − 1 + 2 − 1 + 2 − 1 