Mathematics 1229A/B Lecture Notes - Lecture 23: Asana, Axa
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Propertiesof Determinants
Theorem
letAand Abe
square
matricies
that
are
thethesameexceptthat
inonerow or in one
column ofA
each
entry of AismultipliedbyascalarcThende
ta ec
de
1A Thatis ccanbe
factoredout ofthe
row oncolumn
Example
letAIg weknow
that detail
del
B3
de
1A
LetBµkg 32 FinddetB 347
21
Example
LetALac
bd bea22matrix
suchthat de
1A 4Findthedeterminantof BLac
bd
del
B2
de
1A
a2C4
8
Example
Let ALacbd bea22matrix
such
thatdetA 4Find
thedeterminantofB26
del
B3
detµd3det 22 bd
32det Ibd
6L4
24
Example
letAgadabe bea33matrix
suchthatdetA 1Find
thedeterminant of
I
det
B2
de
1gd
Eben
Egf
212 det Idg
g
2C
22det god
i8
Cl
8
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Theorem
let AbethesquarematrixofordernThen
DetCA ch
de
1A
Example delCAC1de
1A
Example
betAgFinddeta
i2io
4a22
de
1Aa2det
µIfII
SuZdag
2
Co
o
Theorem
if asquare
matrixAhasarowthatis ascalar
multipleofanotherrow orcolumnthat is a
scalar
multipleof
anothercolumn
1thende1A0
Example
letAIda
abe 2and BIg Idg ThendelAoanddel
Bo
Example
aµ22,1 Findde
1A
c2e de
1Ao
Example
LetAIg 2Find
de
1A
deta ade
1A aade
1Aaa3
det
Aand
et
Acy
Idef gIz
Is ooo
Rs 7RThende
1A o
Example
LetAI4and BIFindde
1AandDet
B
whitegnu126 and 38735 others unlocked
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MATH 1229A/B Full Course Notes
Verified Note
60 documents
Document Summary
Theorem leta and a besquarematriciesthatarethethesameexceptthatinonerow or in onecolumn ofa eachentry of a ismultipliedbya scalarc thendeta e cde1a thatis c canbefactoredout ofthe row oncolumn. Leta lacbd bea 2 2 matrixsuchthat de1a 4 findthedeterminantof b lacbd delb 2de1a a2c4. Let a lacbd bea 2 2 matrixsuchthatdeta 4 findthedeterminantofb 26. Example let a gadabe be a 3 3matrixsuchthatdeta 1 findthedeterminant of. 4 a 2 2 de1aa 2det i f i i. Theorem if asquarematrixahas a rowthatis ascalarmultipleofanotherrow orcolumnthat is ascalarmultipleof anothercolumn1thende1a 0. 2 and b ig idg thendela o anddelb o a 22,1 findde1a c 2e de1a o. Findde1a deta a de1a aade1a a a3deta andetacy. 4 l use4 casca to de1b andetb acadetbat abdetbs. Example let a idg andde1a 4 finddetbwhere b a ebnadg de1be de1a. Ra ry deta cn de1 gig ig deta i b 5c2 so. Rowoperations sofar wehaveseenhowdeterminantsofsquarematriciesbehavewithrespecttotwoofthethreeelementaryrow operations if a rowis multipliedbyascalarthedeterminantismultipliedbythesamescalar iftworowsareinterchangedthesignofthedeterminant is reversed. Theorem if a scalarmultipleofonerowcorcolumn isaddedtoanotherrowcorcolumn of a squarematrix thedeterminantis unchanged.