[線代] orthogonal complement

[mqazz1 (無法顯示)]

find the orthogonal complement of the subspace of R^3 spanned by

(1, 2, 1)^T and (1, -1, 2)^T

=================================================================

我這樣寫

 [a] [1]                 [a] [ 1]
<[b],[2]> = 0           <[b],[-1]> = 0
 [c],[1]                 [c] [ 2]

解聯立 c = 3b

     [ a]          [1]  [0]
span{[ b]} => span{[0], [1]}
     [3b]          [0]  [3]


解答是(-5, 1, 3)^T

請問我是什麼地方錯了?

謝謝!!

--
※ 發信站: 批踢踢實業坊(ptt.cc) 
◆ From: 61.228.28.13
推 smartlwj    :c=3b 然後代回a+2b+c=0 => a=-5b
→ mqazz1      :謝謝!!