Vector problem

• XiaoWangZi

  15 Apr 09, 15:37

  Can help me solve this two question?

  

  As i cannot insert the image,pls go to this website:http://tinypic.com/view.php?pic=4vfmsy&s=5

   

  Sorry for the inconvience

• d3sT1nY

  15 Apr 09, 15:55

  

• dkcx

  15 Apr 09, 15:56

  3a) Does O means the origin? If it does then its easy to find the coordinates of Z since OZ is the same as the vector for XY. Therefore,

  O= (0,0), X = (5,1) Y = (8,6) Z = (3,5) 

  ZX = (2, -4)

  bi) Lazy to think of proving question so skipping that.

  bii) Since P lies on the x axis, y = 0,
  1-4k = 0
  k = 1/4

  Unless i made a mistake, my P would not lie on x axis though since my entire diagram does not cut the x-axis anywhere...

  4)

  BA = 12a-4b
  BS = 1/4(BA) = 3a-b
  OS = OB + BS = 4b + (3a-b) = 3a +3b = 3(a+b)
  
  BQ = 4/3 (OA) = 16a
  AQ = AB + BQ = 4b-12a + 16a = 4a + 4b = 4(a+b)

  AQ and OS are parallel to each other  with different magnitude
      

• Forbiddensinner

  15 Apr 09, 16:13

  For 3 b (i),

  XP=k ZX

       =(2k, -4k)

  OP=OX+XP

        =(5,1) + (2k, -4k)

        =(5+2k, 1-4k )