[線代] 一些內積的問題

[mqazz1 (無法顯示)]

1. evaluate u．v and ||u*v|| if ||u||=2, ||v||=5, ||u+v||=1, ||u-v||=5


       [0 0 -2]
2. A = [1 2  1], find the orthonormal basis for the column space of A
       [1 0  3]

   為什麼書上先算eigenvalue = 1, 2

   然後{[-2, 1, 1]}為1對應的eigenspace之一basis

   {[-1, 0, 1], [0, 1, 0]}為2對應的eigenspace之一basis

   請問這個是題目要求的嗎?


3. the area of a triangle with two sides given by a = <1, 3, -1> and

   b = <2, -1, 2> is ?

     [ 1  2]
   A=[ 3 -1]
     [-1  2]
                                   T
   為什麼area = (1/2) * 根號[ det(A A) ]


謝謝

--
※ 發信站: 批踢踢實業坊(ptt.cc) 
◆ From: 61.228.25.26