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1. suppose A is an n*n matrix with the property that A^2=A. Let a1,a2,...,an 屬於 R^n be the column vectors of A and A1,...,An 屬於 R^n be the row vectors of A. Let C(A) = span(a1,...,an) and R(A) = span(A1,...,An) be the column space and the row space of A, respectively. Define E(A) = {x 屬於 R^n|x=Ax} F(A) = {x 屬於 R^n|x=u-Au for some u 屬於 R^n} Find the following four sets: C(A) 交集 E(A),N(A) 交集 F(A),C(A) 交集 N(A), C(A)+N(A). 2. 假設A,B 屬於 R^(n*n),若A,B正交相似 則 A為正定矩陣 <=> B為正定矩陣 成立嗎 請各位幫忙 感謝 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 220.131.66.196
iyenn:!_! 02/25 00:27
luckysky1:2.相似eigenvalue就會一樣,都會大於0 02/25 08:16
polomoss:1. C(A)=E(A),N(A)=F(A) 所以答案依序 C(A),N(A),{0},R 02/25 09:06
vivaptt:請問為什麼N(A)=F(A)@@ 02/25 12:00
Lukewind:x=u-Au , Ax=A(u-Au)=Au-A^2u=Au-Au=0 02/25 13:28