Matlab 第一章习题解答Word文档格式.docx

Matlab 第一章习题解答Word文档格式.docx

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Relationaloperators.

eq-Equal==

ne-Notequal~=

lt-Lessthan<

gt-Greaterthan>

le-Lessthanorequal<

=

ge-Greaterthanorequal>

Logicaloperators.

relop-Short-circuitlogicalAND&

&

relop-Short-circuitlogicalOR||

and-Element-wiselogicalAND&

or-Element-wiselogicalOR|

not-LogicalNOT~

xor-LogicalEXCLUSIVEOR

any-Trueifanyelementofvectorisnonzero

all-Trueifallelementsofvectorarenonzero

Specialcharacters.

colon-Colon:

paren-Parenthesesandsubscripting（）

paren-Brackets[]

paren-Bracesandsubscripting{}

punct-Functionhandlecreation@

punct-Decimalpoint.

punct-Structurefieldaccess.

punct-Parentdirectory..

punct-Continuation...

punct-Separator,

punct-Semicolon;

punct-Comment%

punct-Invokeoperatingsystemcommand!

punct-Assignment=

punct-Quote'

transpose-Transpose.'

ctranspose-Complexconjugatetranspose'

horzcat-Horizontalconcatenation[,]

vertcat-Verticalconcatenation[;

]

subsasgn-Subscriptedassignment（）,{},.

subsref-Subscriptedreference（）,{},.

subsindex-Subscriptindex

Bitwiseoperators.

bitand-Bit-wiseAND.

bitcmp-Complementbits.

bitor-Bit-wiseOR.

bitmax-Maximumfloatingpointinteger.

bitxor-Bit-wiseXOR.

bitset-Setbit.

bitget-Getbit.

bitshift-Bit-wiseshift.

Setoperators.

union-Setunion.

unique-Setunique.

intersect-Setintersection.

setdiff-Setdifference.

setxor-Setexclusive-or.

ismember-Trueforsetmember.

Seealsoarith,relop,slash,function_handle.

arith

Arithmeticoperators.

+Plus.

X+YaddsmatricesXandY.XandYmusthavethesame

dimensionsunlessoneisascalar（a1-by-1matrix）.

Ascalarcanbeaddedtoanything.

-Minus.

X-YsubtractsmatrixXfromY.XandYmusthavethesame

dimensionsunlessoneisascalar.Ascalarcanbesubtracted

fromanything.

*Matrixmultiplication.

X*YisthematrixproductofXandY.Anyscalar（a1-by-1matrix）

maymultiplyanything.Otherwise,thenumberofcolumnsofXmust

equalthenumberofrowsofY.

.*Arraymultiplication

X.*Ydenoteselement-by-elementmultiplication.XandY

musthavethesamedimensionsunlessoneisascalar.

Ascalarcanbemultipliedintoanything.

^Matrixpower.

Z=X^yisXtotheypowerifyisascalarandXissquare.Ifyisan

integergreaterthanone,thepoweriscomputedbyrepeated

multiplication.Forothervaluesofythecalculation

involveseigenvaluesandeigenvectors.

Z=x^YisxtotheYpower,ifYisasquarematrixandxisascalar,

computedusingeigenvaluesandeigenvectors.

Z=X^Y,wherebothXandYarematrices,isanerror.

.^Arraypower.

Z=X.^Ydenoteselement-by-elementpowers.XandY

musthavethesamedimensionsunlessoneisascalar.

Ascalarcanoperateintoanything.

Relop

Relationaloperators.

<

>

Thesixrelationaloperatorsare<

<

=,>

>

=,==,and~=.

A<

BdoeselementbyelementcomparisonsbetweenAandB

andreturnsamatrixofthesamesizewithelementssettological

1（TRUE）wheretherelationistrueandelementssettological0

（FALSE）whereitisnot.AandBmusthavethesamedimensions

（oronecanbeascalar）.

&

Element-wiseLogicalAND.

A&

Bisamatrixwhoseelementsarelogical1（TRUE）wherebothA

andBhavenon-zeroelements,andlogical0（FALSE）whereeitherhas

azeroelement.AandBmusthavethesamedimensions（oronecan

beascalar）.

Short-CircuitLogicalAND.

BisascalarvaluethatisthelogicalANDofscalarAandB.

Thisisa"

short-circuit"

operationinthatMATLABevaluatesBonly

iftheresultisnotfullydeterminedbyA.Forexample,ifAequals

0,thentheentireexpressionevaluatestological0（FALSE）,regard-

lessofthevalueofB.Underthesecircumstances,thereisnoneed

toevaluateBbecausetheresultisalreadyknown.

|Element-wiseLogicalOR.

A|Bisamatrixwhoseelementsarelogical1（TRUE）whereeither

AorBhasanon-zeroelement,andlogical0（FALSE）wherebothhave

zeroelements.AandBmusthavethesamedimensions（oronecan

||Short-CircuitLogicalOR.

A||BisascalarvaluethatisthelogicalORofscalarAandB.

1,thentheentireexpressionevaluatestological1（TRUE）,regard-

lessofthevalueofB.Underthesecircumstances,thereisnoneed

~Logicalcomplement（NOT）.

~Aisamatrixwhoseelementsarelogical1（TRUE）whereAhaszero

elements,andlogical0（FALSE）whereAhasnon-zeroelements.

xorExclusiveOR.

xor（A,B）islogical1（TRUE）whereeitherAorB,butnotboth,is

non-zero.SeeXOR.

Slash

Matrixdivision.

\Backslashorleftdivision.

A\BisthematrixdivisionofAintoB,whichisroughlythe

sameasINV（A）*B,exceptitiscomputedinadifferentway.

IfAisanN-by-NmatrixandBisacolumnvectorwithN

components,oramatrixwithseveralsuchcolumns,then

X=A\BisthesolutiontotheequationA*X=Bcomputedby

Gaussianelimination.AwarningmessageisprintedifAis

badlyscaledornearlysingular.A\EYE（SIZE（A））producesthe

inverseofA.

IfAisanM-by-NmatrixwithM<

or>

NandBisacolumn

vectorwithMcomponents,oramatrixwithseveralsuchcolumns,

thenX=A\Bisthesolutionintheleastsquaressensetothe

under-oroverdeterminedsystemofequationsA*X=B.The

effectiverank,K,ofAisdeterminedfromtheQRdecomposition

withpivoting.AsolutionXiscomputedwhichhasatmostK

nonzerocomponentspercolumn.IfK<

Nthiswillusuallynot

bethesamesolutionasPINV（A）*B.A\EYE（SIZE（A））producesa

generalizedinverseofA.

/Slashorrightdivision.

B/AisthematrixdivisionofAintoB,whichisroughlythe

sameasB*INV（A）,exceptitiscomputedinadifferentway.

Moreprecisely,B/A=（A'

\B'

）'

.See\.

./Arrayrightdivision.

B./Adenoteselement-by-elementdivision.AandB

Ascalarcanbedividedwithanything.

.\Arrayleftdivision.

A.\B.denoteselement-by-elementdivision.AandB

function_

FUNHANDLE=@FUNCTION_NAMEreturnsahandletothenamedfunction,

FUNCTION_NAME.AfunctionhandleisaMATLABvaluethatprovidesa

meansofcallingafunctionindirectly.Youcanpassfunction

handlesincallstootherfunctions（whichareoftencalledfunction

functions）.Youcanalsostorefunctionhandlesindatastructuresfor

lateruse（forexample,asHandleGraphicscallbacks）.Afunction

handleisoneofthestandardMATLABdatatypes.Itsclassis

'

function_handle'

.

FUNHANDLE=@（ARGLIST）EXPRESSIONconstructsananonymousfunctionand

returnsahandletothatfunction.Thebodyofthefunction,tothe

rightoftheparentheses,i