10 Bessel FunctionsKelvin Functions

§10.63 Recurrence Relations and Derivatives

Contents
  1. §10.63(i) berν⁡x, beiν⁡x, kerν⁡x, keiν⁡x
  2. §10.63(ii) Cross-Products

§10.63(i) berν⁡x, beiν⁡x, kerν⁡x, keiν⁡x

Let fν⁢(x), gν⁢(x) denote any one of the ordered pairs:

10.63.1 berν⁡x,beiν⁡x;
beiν⁡x,−berν⁡x;
kerν⁡x,keiν⁡x;
keiν⁡x,−kerν⁡x.

Then

10.63.2 fν−1⁢(x)+fν+1⁢(x) =−(ν⁢2/x)⁢(fν⁢(x)−gν⁢(x)),
fν+1⁢(x)+gν+1⁢(x)−fν−1⁢(x)−gν−1⁢(x)=2⁢2⁢fν′⁢(x),
fν′⁢(x) =−(1/2)⁢(fν−1⁢(x)+gν−1⁢(x))−(ν/x)⁢fν⁢(x),
fν′⁢(x) =(1/2)⁢(fν+1⁢(x)+gν+1⁢(x))+(ν/x)⁢fν⁢(x).
10.63.3 2⁢ber′⁡x =ber1⁡x+bei1⁡x,
2⁢bei′⁡x =−ber1⁢x+bei1⁢x.
10.63.4 2⁢ker′⁡x =ker1⁢x+kei1⁢x,
2⁢kei′⁡x =−ker1⁢x+kei1⁢x.

§10.63(ii) Cross-Products

Let

10.63.5 pν =berν2⁡x+beiν2⁡x,
qν =berν⁡x⁢beiν′⁡x−berν′⁡x⁢beiν⁡x,
rν =berν⁡x⁢berν′⁡x+beiν⁡x⁢beiν′⁡x,
sν =(berν′⁡x)2+(beiν′⁡x)2.

Then

10.63.6 pν+1 =pν−1−(4⁢ν/x)⁢rν,
qν+1 =−(ν/x)⁢pν+rν=−qν−1+2⁢rν,
rν+1 =−((ν+1)/x)⁢pν+1+qν,
sν =12⁢pν+1+12⁢pν−1−(ν2/x2)⁢pν,

and

10.63.7 pν⁢sν=rν2+qν2.

Equations (10.63.6) and (10.63.7) also hold when the symbols ber and bei in (10.63.5) are replaced throughout by ker and kei, respectively.