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  • 8/16/2019 Chapter1 Algebra (1)

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    1.抽象代數導論 (Introduction to Abstract Algebra)

    -

    2.張量分析 (Tensor Analysis)

    -

    3.正交函數展開 (Orthogonal Function Expansion)

    -

    4.格林函數 (Green's Function)

    -

    5.變分法 (Calculus of ariation)

    -

    6.攝動理論 (!erturbation Theory)

    "#$%& 高等工程數學  ※ 先修課程:微積分 工程數學 ( 一 )-( 三

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    eference*+ ,ir-hoff. G+. /ac0ane. 1+. A Survey of Modern Algebra. &nd ed. The /ac2illan Co. "e3 4or-. *#56+

    2 . 徐誠浩 . 抽象代數 - 方法導引 . 復旦大學 . *#%#+

    7+ Arangno. 8+ C+. Schaum’s Outline of Theory and Problems of Abstract Algebra. /cGra39:ill Inc. *###+

    ;+ 8es-ins. o?ano?ich Inc. *##+

    $+ :off2an. @+. @une. +. Linear Algebra. &nd ed. The 1outheast ,oo- Co. "e3 >ersey. *#5*+

    5+ /cCoy. "+ :+. Fundamentals of Abstract Algebra. expanded ?ersion. Allyn B ,acon Inc. ,oston. *#5&+

    %+ :ildebrand. F+ ,+. Methods of Applied Mathematics. &nd ed. !rentice9:all Inc. "e3 >ersey. *#5&++

    #+ ,urton. 8+ /+. An ntroduction to Abstract Mathematical Systems. Addison9

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    8a?id :ilbert8a?id :ilbert BornBorn  >anuary &7. *%$& anuary &7. *%$&

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    !hilip /+ /orse!hilip /+ /orse

    HHOperationsOperations research is anresearch is anapplied science utiliing all -no3napplied science utiliing all -no3n

    scientific techniues as tools inscientific techniues as tools in

    sol?ing a specific proble2+Jsol?ing a specific proble2+J

    Founding O1A !resident (*#6&)Founding O1A !resident (*#6&)

    ,+1+ !hysics. *#&$. Case InstituteK,+1+ !hysics. *#&$. Case InstituteK

    !h+8+ !hysics. *#. !rinceton!h+8+ !hysics. *#. !rinceton

    Dni?ersity+Dni?ersity+

    Faculty 2e2ber at /IT. *#7*9*#$#+Faculty 2e2ber at /IT. *#7*9*#$#+

    /ethods of Operations esearch/ethods of Operations esearch

    Lueues. In?entories. and /aintenanceLueues. In?entories. and /aintenance

    0ibrary Effecti?eness0ibrary Effecti?eness

    Luantu2 /echanicsLuantu2 /echanics

    /ethods of Theoretical !hysics/ethods of Theoretical !hysics

    ibration and 1oundibration and 1ound

    Theoretical AcousticsTheoretical Acoustics

    Ther2al !hysicsTher2al !hysics

    :andboo- of /athe2atical Functions. 3ith For2ulas.:andboo- of /athe2atical Functions. 3ith For2ulas.

    Graphs. and /athe2atical TablesGraphs. and /athe2atical Tables

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    Francis ,+ :ildebrandFrancis ,+ :ildebrand

    George Arf-enGeorge Arf-en

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    Introduction to Abstract AlgebraIntroduction to Abstract Algebra

    抽象代數導論抽象代數導論

    M !reli2inary notions!reli2inary notionsM 1yste2s 3ith a single operation1yste2s 3ith a single operationM /athe2atical syste2s 3ith t3o operations/athe2atical syste2s 3ith t3o operationsM /atrix theory an algebraic ?ie3/atrix theory an algebraic ?ie3

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    -

    /01-

      34 -

    抽象代數56

    ( ) ( ) ( ) ( ) RV  R R R ,,,,,,,   •+•+78

    eaaaa   =+=+   −− 11

    ( )•, R

    性之分佈對、   +•

    ( ) ( ) ( )

    ( ) ( ) ( )acabacb

    cabacba

    •+•=•+•+•=+•

    349

    :;

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    群胚  Groupoid

    M  A goupoid 2ust satisfy

      is closed under the rule of co2bination R

    ( )+, R

    R  baR  b,a   ∈+⇒∈∀

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    M Ex+ Consider the operation defined on the set 1N

    *.&.7P by the operation table belo3+

    Fro2 the table. 3e see

    & (* 7)N& 7N& but (& *) 7N7 7N*The associati?e la3 fails to hold in this groupoid(1. )

    &  

    *  

     7 

    *  * & 7

    *  

    &  

     7 

    *  

     7  

     7  

    &  

    ∗ ∗ ∗∗ ∗∗ ∗

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    M  A se2igroup is a groupoid 3hose

    operation satisfies the associati?e la3+

      (groupoid)

    半群 1e2igroup

    ( ) ( ) c bac baR c, b,a   ++=++⇒∈∀

    R  baR  b,a   ∈+⇒∈∀

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    M Ex+ If the operation is defined on by a b N 2ax a.b P.that is a b is the larger of the ele2ents a and b. or

    either one if aNb+

      a (b c) N 2ax a. b. c P N (a b) c

      that sho3s to be a se2igroup

    M If and is a se2igroup. then

     proof.

     

     ) ,(R#  ∗

    ∗∗

    ∗ ∗   ∗ ∗

    #  R   ∗

     Rd c,b,a,   ∈  )(R,+d)c)((bad)(cb)(a   +++=+++

    d)(cb)(a

     xb)(a

     xbyd)(c denoted   x)(ba

    d))(c(bad)c)((ba

    +++=++=

    +++=+++=+++

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    M  A se2igroup ha?ing an identity ele2entfor the operation is called a 2onoid+

      (groupoid)  (se2igroup)

     

    單 /onoid

    ( )+, R+

    aaeeaR a   =+=+⇒∈∃∈∀  Re

    e

    R  baR  b,a   ∈+⇒∈∀

    ( ) ( ) c bac baR c, b,a   ++=++⇒∈∀

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    Ex+ ,oth the se2igroups and are instances of2onoids

      for each

    The e2pty set is the identity ele2ent for the unionoperation+

      for each

    The uni?ersal set is the identity ele2ent for the

    intersection operation+

     ) ,(S U    ) ,(S U  

      A A A   =ϕ=ϕ   U  A ⊆

      A AU U  A   ==   U  A ⊆

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    群 Group

    M  A 2onoid 3hich each ele2ent of has

    an in?erse is called a group

    (groupoid)

      (se2igroup)

      (2onoid)

    ( )+, R  R

    R  baR  b,a   ∈+⇒∈∀

    ( ) ( ) c bac baR c, b,a   ++=++⇒∈∀

    aaeeaR a   =+=+⇒∈∃∈∀  ReeaaaaR aR a 1-1-1 =+=+⇒∈∃∈∀   −

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    M If is a group and .then

    Proof. all 3e need to sho3 is that

      fro2 the uniueness of the in?erse of 

      3e 3ould conclude

    a si2ilar argu2ent establishes that

    ( )+, R  Rba,   ∈ -1-1-1 abb)(a   +=+

    eb)(a )a(b )a(bb)(a -1-1-1-1 =+++=+++

    ba +-1-1-1 abb)(a   +=+

    e

    aa

     )a(ea

     )a )b((ba )a(bb)(a

    1-

    1-

    -1-1-1-1

    =+=

    ++=

    +++=+++

    eb)(a )a(b -1-1 =+++

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    Co22utati?e "交#$

     group

    1-1-1

    monoid 

     semigroup

     groupoid 

    eaaaa Ra Ra

    aaeea Re Racb)(ac)(ba Rcb,a,

     Rba Rba,

    abba Rba,

    =+=+⇒∈∃∈∀

    =+=+⇒∈∃∈∀ ++=++⇒∈∀

    ∈+⇒∈∀+=+⇒∈∀

    Co!!utative

    "roupoid Co!!utative

    se!i"roup

    Co!!utative !onoid

    Co!!utative "roup

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    M Ex+ consider the set of nu2ber and the

    operation of ordinary 2ultiplication. and represents

    integer+

    *+ Closure

    &+  Associate property

    7+ Identity ele2ent

    ;+ Co22utati?e property

      is a co22utati?e 2onoid+

     Z}ba,!b"aS    ∈+=

    S !bc)(ad !bd)(ac )!d (c )!b(a Z d c,b,a,   ∈+++=+•+⇒∈∀

    [ ] [ ]  )!  (e )!d (c )!b(a )!  (e )!d (c )!b(a   +•+•+=+•+•+

     Z  # e,d,c,b,a,   ∈∀

    !$11   +=

     )!b(a )!d (c )!d (c )!b(a   +•+=+•+

     Z d c,b,a,   ∈∀

     )(S,•∴

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    ing %M  A ring is a none2pty set 3ith t3o binary

    operations and on such that*+ is a co22utati?e group

    &+ is a se2igroup

    7+ The t3o operations are related by the distributi?e

    la3s

     ) ,(R,   •+

     semigroup

     groupoid 

    cb)(ac)(ba Rcb,a, Rba Rba,

    ••=••⇒∈∀∈•⇒∈∀

    a)(ca)(bac)(b 

    c)(ab)(ac)(ba Rcb,a,

    •+•=•+

    •+•=+•⇒∈∀

     R

    +   •  R )(R,+

     )(R,• group

    1-1-1

    monoid 

     semigroup

     groupoid 

    eaaaa Ra Ra

    aaeea Re Racb)(ac)(ba Rcb,a,

     Rba Rba,

    abba Rba,

    =+=+⇒∈∃∈∀

    =+=+⇒∈∃∈∀++=++⇒∈∀

    ∈+⇒∈∀+=+⇒∈∀

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    M  A ring consists of a none2pty set and t3o

    operations. called addition and 2ultiplication and denoted

    by and . respecti?ely. satisfying the reuire2ents1. R is closed under addition

    2. Commutative

    3. Associative

    4. Identity element

    !. Inverse

    ". R is closed under multi#lication

    $. Associate

    %. &istributive la'

     ) ,(R,   •+

    +   •

    a)(ca)(bac)(bc)(ab)(ac)(ba%& 

    cb)(ac)(ba'& 

     Rba& 

    $(-a)a Ra& 

    aa$$a R$*& 

    cb)(ac)(ba+& 

    abba!& 

     Rba1& Rcb,a,

     group

    1-

    •+•=•+∧•+•=+•

    ••=••∈•

    =+⇒∈∃=+=+⇒∈∃

    ++=+++=+

    ∈+⇒∈∀

     R

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    /onoid ing  單%

    M  A 2onoid ring is a ring 3ith identity that is a

    se2igroup 3ith identity 

    monoid 

     semigroup

     groupoid 

     group

    1-1-1

    monoid 

      semigroup

     groupoid 

    aaeea Re 

    a)(ca)(bac)(b 

    c)(ab)(ac)(ba 

    cb)(ac)(ba 

     Rba 

    eaaaa Ra 

    aaeea Re 

    cb)(ac)(ba 

     Rba 

    abba Rcb,a,

    =•=•⇒∈∃⇒•+•=•+

    ∧•+•=+•⇒••=••⇒

    ∈•⇒

    =+=+⇒∈∃

    =+=+⇒∈∃

    ++=++⇒

    ∈+⇒+=+⇒∈∀

    −Ring

    Monoid ring

     ) ,(R,   •+

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    M ing 3ith co22utati?e property

    abb  a 

    a)(ca)(bac)(bc)(ab)(ac)(b  a 

    cb)(ac)(b  a 

     Rb  a 

    eaaaa Ra 

    aaeea Re 

    cb)(ac)(b  a abb  a 

     Rba Ra,b,c

    ---

    •=•∧•+•=•+∧•+•=+•

    ∧••=••∧∈•

    ∧=+=+⇒∈∃

    ∧=+=+⇒∈∃∧++=++

    ∧+=+

    ∧∈+⇒∈∀

    111

     ) ,(R,   •+

    Co!!utative

    Co!!utative !onoid Rin"

    aaeea Re 

    a)(ca)(bac)  (b 

    c)(ab)(ac)(ba 

    cb)(ac)(ba 

     Rba 

    eaaaa Ra 

    aaeea Re 

    cb)(ac)(ba 

     Rba 

    abba Rb,ca

    1-1-1

    =•=•⇒∈∃⇒

    •+•=•+∧•+•=+•⇒

    ••=••⇒∈•⇒

    =+=+⇒∈∃ =+=+⇒∈∃

    ++=++⇒∈+⇒

    +=+⇒∈∀

    ,

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    1ubring %

    M The triple is a subring of the ring

    *+ is a none2pty subset of 

    &+ is a subgroup of 

    7+ is closed under 2ultiplication

     ) ,(S,   •+  ) ,(R,   •+

     )(S,+

    S    •

     )(R,+

     R

    S ba 

    eaaaaS a 

    aaeeaS e 

    cb)(ac)(ba 

    S ba 

    abbaS a,b,c

     RS 

    1-1-1-

    ∈•

    ∧=+=+⇒∈∃

    ∧=+=+⇒∈∃

    ∧++=++

    ∧∈+

    ∧+=+⇒∈∀

    ∧⊆

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    M The 2ini2al set of conditions for deter2ining subrings

    0et be ring and Then the triple

    is a subring of if and only if 

    *+ Closed under differences

    &+ Closed under 2ultiplication

    M Ex+ 0et then is a subring of

    . since

    This sho3s that is closed under both differences and

    products+

     RS  ∈≠ϕ ) ,(R,   •+  ) ,(S,   •+ ) ,(R,   •+

    S ba 

    S b-aS ba,

    ∈•∈⇒∈∀

     Z}ba,+b"aS    ∈+=  ) ,(S,   •+

    numbersrea o a set is R ), , ,(R## 

    •+integerso#  set teis Z  Z,d c,b,a,   ∈∀

    S +ad)(bc+bd)(ac )+d (c )+b(a

    S +d)-(bc)-(a )+d (c- )+b(a

    ∈+++=+•+

    ∈+=++

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    Field &M  A field is a co22utati?e 2onoid ring in

    3hich each nonero ele2ent has an in?erse under

     ) ,(F,   •+

    8efinition of Field8efinition of Field

    cabacba . 

     . 

     . 

     .  . 

     . 

    •+•=+•∈•−

    +

    •+

    )(

    ,

    ,

    ,,

     .cb.a.ele2entsof tripleeachFor (7)

    *Kidentity3ithgroup.eco22utati?ais)((&)

    'Kidentity3ithgroup.eco22utati?ais)((*)

    thatsuchtion.2ultiplicaandadditioncalled.onandset

    none2ptyof consisting)(syste2al2athe2aticaisfield A

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    ector  '量

    M  An n9co2ponent. or n9di2ensional. ?ector is an ntuple of real nu2bers 3ritten either in a ro3 or in a

    colu2n+

    M o3 ?ector

    M Colu2n ?ector 

      called the co2ponents of the ?ectorn is the di2ension of the ?ector 

     

    ( )n!1  x x x ,,,  

         

     

     

     

     

    n

    !

    1

     x

     x

     x

    #

    k    R x   ∈

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    ector space '量()

    M  A ?ector space( or linear space)o?er the field F consists of the follo3ing

    *+ A co22utati?e group 3hose ele2ents are called

    ?ectors+

    V(.) ) ), , ),(.,((V, or •++

     group

    1-1-1

    monoid 

     semigroup

     groupoid 

    eaaaaV aV a

    aaeeaV eV a

    cb)(ac)(baV a,b,c

    V baV a,b

    abbaV a,b

    =+=+⇒∈∃∈∀

    =+=+⇒∈∃∈∀

    ++=++⇒∈∀

    ∈+⇒∈∀+=+⇒∈∀

     )(V, +

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    &+ A field 3hose ele2ents are called scalars+

    eaaaa . a 

    aaeea . e 

    a)(ca)(bac)  (b 

    c)(ab)(ac)(ba 

    cb)(ac)(ba  . ba 

    eaaaa . a 

    aaeea . e 

    cb)(ac)(ba 

     . ba 

    abba . b,ca

    1-1-1

    1-1-1

    =•=•⇒∈∃⇒

    =•=•⇒∈∃⇒•+•=•+

    ∧•+•=+•⇒••=••⇒

    ∈•⇒

    =+=+⇒∈∃

    =+=+⇒∈∃++=++⇒

    ∈+⇒

    +=+⇒∈∀

    ,

     ) ,(F,   •+

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    7+ An operation of scalar 2ultiplication connecting the

    group and field 3hich satisfies the properties

    ∀ ∈ ∈ ∈

    + = +

    =

    + = +

    =

    o

    o o o

    o o o o

    o o o

    o

    * & * &

    * & * &

    (a) and . there is defined an ele2ent K

    (b) ( ) ( ) ( )K

    (c) ( ) ( ).

    (d) ( ) ( ) ( )K

    (e) * . 3here * is the field identity ele2ent+

    c F x V c x V  

    c c x c x c x  

    c c x c c x  

    c x y c x c y  

     x x 

    V  is closed under left 2ultiplication by scalars

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    nmi/i/

    nmi/

    nmnm

     0 caac

     0 a Rc

    nm

     0  0 

    ×

    ×

    ××

    ∈=

    ∈∈

    +× +

     

    bytion2ultiplicascalar define.andFor 

    addition+2atrixof operationtheisand2atricesallof 

    settheis3here.begroupeco22utati?the0et

    )()(

    )(

    ),(

    *

    Q ector 1pace

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    tion+2ultiplicascalar under closedis(&) of subgroupais(*)

     V   )+,(),(   ++

    1ubspace '量()

    φ   ≠⊆  V   ,M 0et () be a ?ector space o?er the field

    () is a subspace of ()

    The 2ini2u2 conditions that () 2ust satisfy to be a subspace are

    .

    +,

     cx . c  x

      y x  y x

     i2plyand

     i2plies

    ∈∈∈∈+∈

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    M If () and /() are ?ector spaces o?er the sa2e field. then the

      2apping f 0 / is said to be operation-preser2ing  if 

    ),()(

    ),()()(

     xc cx  

     y   x   y x  

    =+=+

     

    +and.ele2entsof pair   . cV  y x   ∈∈∀

    f   preser?es

    () and /() are algebraically eui?alent 3hene?er there exists a

    one9to9one operation9preser?ing function fro2  onto /

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    0inear Transfor2ations +$,#

    M 0et  and  be ?ector spaces+ A linear transformation from  into

     is a function  fro2 the set  into  3ith the follo3ing t3oproperties

    .),()(

    .,),()()(

    α α α   scalarsand(ii)

     (i)

    V  x x3  x3 

    V  y x y3  x3  y x3 

    ∈∀=

    ∈∀+=+

    ()

     is function fro2

     to

    . 5)( V  x x3    ∈

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    0et  and  be ?ector spaces o?er the field  and let  be a

    linear transformation fro2  into +

    M The null space ("ernal ) of  is the set of all ?ectors x in  such that (x) 6

    -er O S ( ) 'PT x V T x  = ∈ =

    M If  is finite-dimensional . the ran"  of  is the dimension of the range of  

    and the nullity  of  is the dimension of the null space of +

    M

    M

    M

    M

    M

    -er

    ran

    Th Al b f 0i T f ti

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    U  x x3 S  x3 S   infor )),(())((   =

    The Algebra of 0inear Transfor2ations

    M0et  0 7  and 8 0  be linear transfor2ations. 3ith 7. . and

     ?ector spaces+

    The composition of 8 and

    * &

    * & * &

    * &

      and are ?ectors in . then

    ( )( ) ( ( )) (by definition of )

      ( ( ) ( )) (by linearity of )

     

    if x x  

    ! T x x ! T x x ! T  

    ! T x T x T  

    + = +

    = +

    o o

    * &

    * &

      ( ( )) ( ( )) (by linearity of )

      ( )( ) ( )( ) (by definition of )

    1i2ilarly. 3e ha?e. 3ith in and a scalar.

      ( )

    ! T x ! T x !

    ! T x ! T x ! T  

     x  

    ! T 

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    = +

    = +o o o

    o ( ) ( ( )) (by definition of )

      ( ( )) (by linearity of )

      ( ( )) (by linearity of

     x ! T x ! T 

    ! T x T  

    ! T x 

    α α 

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    ===

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    )

      ( )( ) (by definition of )

    !

    ! T x ! T  α = o o

    t ti f 0i T f ti b / t i

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    epresentation of 0inear Transfor2ations by /atrices

    +$,#-./01

    0et  be an n9di2ensional ?ector space o?er the field +  is a linear

    transfor2ation. and α1, α2,…,αn are ordered bases for + If 

     A

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    α α α 

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    =

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    +++=+++=

     

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    21

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    234 A5 0inear Transfor2ation 

    6 α1, α2,…,αn 7-./

    Inner !roductInner !roduct '量89'量89

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    Inner !roductInner !roduct '量89'量89

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    =

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    ⋅⇒++=++=

    α α 

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    9: 332211

    3

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    It follo3s fro2 the !ythagorean theore2 that the length of the ?ectorIt follo3s fro2 the !ythagorean theore2 that the length of the ?ector

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    It follo3s fro2 the !ythagorean theore2 that the length of the ?ectorIt follo3s fro2 the !ythagorean theore2 that the length of the ?ector

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    −+=−⇒=⇒

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    the2bet3eenanglethebeletandin?ectorsnonerobeand0et 

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    Inner !roduct 1pace '量89()

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    Inner !roduct 1pace '量89()

     y x x,y y x

     x y y x

     y x y x

     y x y x

     5  y 5  x 5  y x

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     x x,x

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    V  x,yV  y x

    nn

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    ),(,

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    spaceproductinner

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    Eigen?alues and Eigen?ectors

    :;

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    rs+eigen?ectothe 

    of 2ultiplesscalar bydeter2inedoriginthethroughlinesthefixes 

    operator linear thecase.thisInly+respecti?e.andrseigen?ecto 

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    ** ** && 77

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    ;; $ I # & %$ I # & %

    ' I # ' %' I # ' %

    TT

    8iagonali ation >?@

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    8iagonaliation >?@

     A suare 2atrix is said to be a diagonal  2atrix if all of its entries are

    ero except those on the 2ain diagonal

    nλ 

    λ 

    λ 

    2

    1

     A linear operator on a finite9di2ensional ?ector space  is diagonali#able if

    there is a basis ?ector for  each ?ector of 3hich is an eigenvector  of T+

    Orthogonaliation of ector 1ets '量-正交@

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    ∑−

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    )eu,(eu v )u(

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    uired t=eo

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     A xxyx. 

    2atrixsy22etricais Ay. A xfor2thein3rittenbecaneuationsof setThe

     

    euationstheobtain3e. 3rite3eIf 

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    nnnnnn

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     y xa xa xa

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     orm9uadratic x xa x xa x xa xa xa xa A

    =≡

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    +++++++≡   −−

    )(

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    Luadratic For2s ABCD

    E        I     

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     t      

     /ii/

    i /i/

    aa

     y xa

    ==

     A A x : y x : y

    Canonical For2 EFCD

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    Canonical For2 EFCD

    L AL A'euationthebydefinedis2atrix A'ne3the3here

     x' A'x'or  x'L ALx'x'L A)x'(L

     x'L xeuationthebyx'of ter2sinexpressedbex?ector the0et

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    TTTT

    =

    ===⇒

    =

     A A

    UU8iagonal 2atrix8iagonal 2atrix

    If the eigen?alues and corresponding eigen?ectors of the real sy22etric 2atrixIf the eigen?alues and corresponding eigen?ectors of the real sy22etric 2atrix

     A are -no3n. a 2atrix L ha?ing this property can be easily constructed A are -no3n. a 2atrix L ha?ing this property can be easily constructed

    nnnn ee Aee A   λ λ    == ,,1111 

    =

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    L

    0et a 2atrix L be constructed in such a 3ay that the ele2ents of the unit ?ectors0et a 2atrix L be constructed in such a 3ay that the ele2ents of the unit ?ectors

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    eigen?ector eigen?ector 

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    e

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    11

    1  

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    /atrixOrthogonal ILL or  LL

     L AL resulttheobtain3eLbyabo?eeuationthe

     of 2e2berseualtheyingpre2ultiplbyandexists.Lin?ersetheThus

    'SLSthatfollo3sitt.independenlinearlyaree.+++++.e?ectorsthe1ince

     LL  Aor  L A

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    1

    2211

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    1212111

    i/i

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    δ λ 

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    λ λ λ 

    iiiii ee x   λ λ    ==⇒   ∑   A A 2

    Ex 0et T be the linear operator on 7 3hich is represented in

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    Ex 0et T be the linear operator on 7 3hich is represented in

      the standard ordered basis by the 2atrix A

     ; A