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2.9.11  Airy functions : Airy_Ai and Airy_Bi

Airy_Ai and Airy_Bi takes as argument a real x.
Airy_Ai and Airy_Bi are two independant solutions of the equation

y′′−x*y=0 

They are defined by :

Airy_Ai(x)=
(1/π) ∫
∞


0
cos(t3/3 + x*t) dt 
Airy_Bi(x)=
(1/π) ∫
∞


0
(e− t3/3 + sin( t3/3 + x*t)) dt

Properties :

 Airy_Ai(x)=Airy_Ai(0)*f(x)+ Airy_Ai′(0)*g(x) 
Airy_Bi(x)=
√
3
(Airy_Ai(0)*f(x) −Airy_Ai′(0)*g(x) )

where f and g are two entire series solutions of

w′′−x*w=0 

more precisely :

f(x)=
∞
∑
k=0
3k⎛
⎜
⎜
⎜
⎜
⎜
⎝
Γ(k+
1
3
)
Γ(
1
3
)
⎞
⎟
⎟
⎟
⎟
⎟
⎠
x3k
(3k)!
g(x)=
∞
∑
k=0
3k⎛
⎜
⎜
⎜
⎜
⎜
⎝
Γ(k+
2
3
)
Γ(
2
3
)
⎞
⎟
⎟
⎟
⎟
⎟
⎠
x3k+1
(3k+1)!

Input :

Airy_Ai(1)

Output :

0.135292416313

Input :

Airy_Bi(1)

Output :

1.20742359495

Input :

Airy_Ai(0)

Output :

0.355028053888

Input :

Airy_Bi(0)

Output :

0.614926627446

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