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10 Bessel FunctionsBessel and Hankel Functions

§10.6 Recurrence Relations and Derivatives

Contents
  1. §10.6(i) Recurrence Relations
  2. §10.6(ii) Derivatives
  3. §10.6(iii) Cross-Products

§10.6(i) Recurrence Relations

With 𝒞ν⁡(z) defined as in §10.2(ii),

10.6.1 𝒞ν−1⁡(z)+𝒞ν+1⁡(z) =(2⁢ν/z)⁢𝒞ν⁡(z),
𝒞ν−1⁡(z)−𝒞ν+1⁡(z) =2⁢𝒞ν′⁡(z).
10.6.2 𝒞ν′⁡(z) =𝒞ν−1⁡(z)−(ν/z)⁢𝒞ν⁡(z),
𝒞ν′⁡(z) =−𝒞ν+1⁡(z)+(ν/z)⁢𝒞ν⁡(z).
10.6.3 J0′⁡(z) =−J1⁡(z), Y0′⁡(z) =−Y1⁡(z),
H0(1)′⁡(z) =−H1(1)⁡(z), H0(2)′⁡(z) =−H1(2)⁡(z).

If fν⁡(z)=zp⁢𝒞ν⁡(λ⁢zq), where p,q, and λ (≠0) are real or complex constants, then

10.6.4 fν−1⁡(z)+fν+1⁡(z) =(2⁢ν/λ)⁢z−q⁢fν⁡(z),
(p+ν⁢q)⁢fν−1⁡(z)+(p−ν⁢q)⁢fν+1⁡(z) =(2⁢ν/λ)⁢z1−q⁢fν′⁡(z).
10.6.5 z⁢fν′⁡(z) =λ⁢q⁢zq⁢fν−1⁡(z)+(p−ν⁢q)⁢fν⁡(z),
z⁢fν′⁡(z) =−λ⁢q⁢zq⁢fν+1⁡(z)+(p+ν⁢q)⁢fν⁡(z).

For results on modified quotients of the form z⁢𝒞ν±1⁡(z)/𝒞ν⁡(z) see Onoe (1955) and Onoe (1956).

§10.6(ii) Derivatives

For k=0,1,2,…,

10.6.6 (1z⁢ddz)k⁡(zν⁢𝒞ν⁡(z)) =zν−k⁢𝒞ν−k⁡(z),
(1z⁢ddz)k⁡(z−ν⁢𝒞ν⁡(z)) =(−1)k⁢z−ν−k⁢𝒞ν+k⁡(z).
10.6.7 𝒞ν(k)⁡(z)=12k⁢∑n=0k(−1)n⁢(kn)⁢𝒞ν−k+2⁢n⁡(z).

§10.6(iii) Cross-Products

Let

10.6.8 pν =Jν⁡(a)⁢Yν⁡(b)−Jν⁡(b)⁢Yν⁡(a),
qν =Jν⁡(a)⁢Yν′⁡(b)−Jν′⁡(b)⁢Yν⁡(a),
rν =Jν′⁡(a)⁢Yν⁡(b)−Jν⁡(b)⁢Yν′⁡(a),
sν =Jν′⁡(a)⁢Yν′⁡(b)−Jν′⁡(b)⁢Yν′⁡(a),

where a and b are independent of ν. Then

10.6.9 pν+1−pν−1 =−2⁢νa⁢qν−2⁢νb⁢rν,
qν+1+rν =νa⁢pν−ν+1b⁢pν+1,
rν+1+qν =νb⁢pν−ν+1a⁢pν+1,
sν =12⁢pν+1+12⁢pν−1−ν2a⁢b⁢pν,

and

10.6.10 pν⁢sν−qν⁢rν=4/(π2⁢a⁢b).