[理工] [線代]內積空間維度問題
98 交大電信
章節是內積空間-正交補空間
題目:
Let A be a 7x5 matrix of rank 4 and let b be a non-zero vector in N(A^T).
What are the dimensions of R(A), N(A), R(A^T), N(A^T) ?
解答是說
dim(R(A)) + dim(N(A)) = 5
dim(R(A^T)) + dim(N(A^T)) = 7
我記得A是a*b的話,應該是有b個vector在a維空間生成
所以這題是5個vector在7維空間生成R(A),總維度是7維
根據維度定理,上面我會寫成dim(R(A)) + dim(N(A)) = 7
然後轉置的話,就變成5x7
7個vector在5維空間生成.. 後面同上
總結來說,就是我的想法和解答剛好相反
請問我是搞錯什麼了嗎? 謝謝解答
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