南京航空航天大学MatrixTheory双语矩阵论期末考试

南航矩阵论等价关系

Student’s Name: Student’s ID No.: College Name: The study of Equivalence Relations Abstract According to some relative definitions and properties, to proof that if B can be obtained from A by performing elementary row operations on A, ~ is an equivalence relation, and to find the properties that are shared by all the elements in the same equivalence class. To proof that if B is can be obtained from A by performing elementary operations, Matrix S A ∈ is said to be equivalent to matrix S B ∈, and ~A B means that matrix S A ∈ is similar to S B ∈, if let S be the set of m m ? real matrices. Introduction The equivalence relations are used in the matrix theory in a very wide field. An equivalence relation on a set S divides S into equivalence classes. Equivalence classes are pair-wise disjoint subsets of S . a ~ b if and only if a and b are in the same equivalence class.This paper will introduce some definitions and properties of equivalence relations and proof some discussions. Main Results Answers of Q1 (a) The process of the proof is as following,obviously IA=A,therefore ~ is reflexive;we know B can be obtained from A by performing elementary row operations on A,we assume P is a matrix which denote a series of elementary row operations on A.Then ,we have PA=B,(A~B),and P is inverse,obviously we have A=P -1B,(B~A).So ~ is symmetric.We have another matrix Q which denote a series of elementary row operations on B,and the result is C,so we have QB=C.And we can obtain QB=Q(PA)=QPA=C,so A~C.Therefore,~ is transitive. Hence, ~ is an equivalence relation on S . (b) The properties that are shared by all the elements in the same equivalence class are as followings: firstly,the rank is the same;secondly,the relation of column is not changed;thirdly,two random matrices are row equivalent;fourthly,all of the matrices

矩阵论解题步骤-期末考试题

1. 广义逆（必考类型）假设s x n 矩阵A 的广义逆为G ，且A 可以满秩分解为A = BC ，A 的秩r(A) = r ，则B 为s x r 矩阵，C 为r x n 矩阵。则G 可表示为： H 1 1 C (CC )(B B)B H H H G --= 例题：步骤：显然，A 要分解为BC ，必须知道A 的秩，故先对A 进行行化简成最简式，r(A)=2，故A 满秩分解为A=（3x2）（2x4）=BC.根据A 的最简式来决定B 和C ，B 由A 最简式中只有1的原列组成，C 由A 的最简式的非零首元行组成。 B = ， C = ，H 11C (CC )(B B)B H H H A --+=，通过计算即可得到A 的广义逆。（若B 、C 中有单位矩阵，那么A 的广义逆表达式可去掉矩阵）性质： 2. 证明r(ABC)r(B)r(AB)+r(BC)+>=

比较重要的性质 (1) ABX=0与BX=0同解 r(AB)=r(B) (2) r(A)=r(H A A ) (3) r(A+B)<=r(A)+r(B) (4) r(AB)<=min[r(A),r(B)] (5) r(AB)>=r(A)+r(B)-n ，其中A=s x n ，B=n x t 步骤：设r(B)=r ，B 的满秩分解为B=HK ，所以ABC=AHKC ， r(ABC)=r(AHKC)>=r(AH)+r(KC)-r （性质（5）） AB=AHK ，故r(AB)<=r(AH)，同理得r(BC)<=r(KC)，（性质（4））从而r(ABC)>=r(AB)+r(BC)-r(B)，原式得证知识点： A ．秩为r 的s x n 矩阵A 必可分解为A=BC ，其中B=s x r ，C=r x n 。该分解称为A 的满秩分解。 3. nxn 2n n 2V {X |AX ,X C }n X ==∈，证明：12=V n C V ⊕ 证明包含两部分，1）证明12V V ⊕是直和等价于证明1 2V {0}V = 2）证明12V n C V ?⊕，12V n C V ?⊕ 步骤：

2016矩阵论试题

第 1 页共 6 页（A 卷）学院系专业班级姓名学号 (密封线外不要写姓名、学号、班级、密封线内不准答题，违者按零分计) …………………………………………密…………………………封……………………………………线………………………………… 考试方式：闭卷太原理工大学矩阵分析试卷（A ）适用专业：2016级硕士研究生考试日期：2017.1.09 时间：120 分钟共 8页一、填空选择题（每小题3分，共30分） 1-5题为填空题： 1. 已知??? ? ? ??--=304021101A ，则1||||A =。 2. 设线性变换1T ，2T 在基n ααα ,,21下的矩阵分别为A ，B ，则线性变换212T T +在基n ααα ,,21下的矩阵为_____________. 3．在3R 中，基T )2,1,3(1--=α，T )1,1,1(2-=α，T )1,3,2(3-=α到基T )1,1,1(1=β， T )3,2,1(2=β，T )1,0,2(3=β的过度矩阵为A = 4. 设矩阵??? ? ? ??--=304021101A ，则 5432333A A A A A -++-= . 5．??? ? ? ? ?-=λλλλλ0010 01)(2A 的Smith 标准形为 6-10题为单项选择题： 6．设A 是正规矩阵，则下列说法不正确的是（）. (A) A 一定可以对角化；（B ）?=H A A A 的特征值全为实数； (C) 若E AA H =，则 1=A ；（D ）?-=H A A A 的特征值全为零或纯虚数。 7．设矩阵A 的谱半径1)(