Determinants and Their Applications in Mathematical Physics

(Chris Devlin) #1

150 4. Particular Determinants


Note thatUij=Vijin general. Since


ψ


m=−mψm−^1 ,

ψ 0 =x+c, (4.11.68)

it follows that


V


=V 11

=





c(1 +x)
i+j+1
+(1−c)x
i+j+1

i+j+1





n− 1

. (4.11.69)

ExpandUandVas a polynomial inc:


U(x, c)=V(x, c)=

n

r=0

fr(x)c

n−r

. (4.11.70)


However, since


ψm=ymc+zm,

wherezmis independent ofc,


ym=(−1)

m

[

(1 +x)

m+1
−x

m+1

m+1

]

, (4.11.71)

y


m
=−mym− 1 ,

y 0 =1, (4.11.72)

it follows from the first line of (4.11.67) thatf 0 , the coefficient ofc


n
inV,

is given by


f 0 =|ym|n

= constant. (4.11.73)

c

n− 1
V(x, c

− 1
)=f 0 c

− 1
+f 1 +

n− 1

r=1

fr+1c

r
,

where


f


1

=

[

c

n− 1
DxV(x, c

− 1
)

]

c=0

,Dx=


∂x

,

=

[

c

n− 1
V 11 (x, c

− 1
)

]

c=0

=

[

c

n− 1





c

− 1
(1 +x)

i+j+1
+(1−c

− 1
)x

i+j+1

i+j+1





n− 1

]

c=0

=E. (4.11.74)

Furthermore,


Dc{c

n
U(x, c

− 1
)}=Dc{c

n
V(x, c

− 1
)},Dc=


∂c

,
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