The Chemistry Maths Book, Second Edition

(Grace) #1

17.5 Properties of determinants 489


(17.40)



  1. Multiplication by a constant


If all the elements of any row (or column) are multiplied by the


same factor λ, the value of the new determinant is λtimes the


value of the old determinant:


(17.41)


EXAMPLE 17.10Examples of Property 2.


A special case isλ 1 = 10 : if all the elements of a row (or column) are zero, the value of


the determinant is zero:


(17.42)



  1. Addition rule


If all the elements of any row (or column) are written as the sum


of two terms the determinant can be written as the sum of two


determinants:


(17.43)


ad b c


ad bc


ad b c


abc


abc


ab


11
11

22
22

33
33

1
11

222

3













=


333

1
11

222

333

c


dbc


dbc


dbc






000


0


2 22

332

abc


abc


=


=×× 223 =××× =


111


143 2233


111


143


123


144


369


246 2


8


12


3


9


27


189


31227


2


13


19


327


22


11


14


36


==×


λλλ


λ


abc


abc


abc


abc


abc


abc


1
11

222

333

1
11

222

333

=


abc


abc


abc


aaa


bbb


ccc


1
11

222

333

1
23

123

123

=

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