THE HYPERGEOMETRIC FUNCTION
233
Eliminating F(«, /3, 7 — 1, x) from 1), 3) gives
(/3 - /3, 7, 2;) + uF (a + 1, /3, 7, cr)
- A^(«, /3 + 1, 7, x) = 0. (4
Permuting a, ¡3 in 2) gives
(7 — a — (3)F(a, /3, 7, 2;) + /3(1 — 2:)jP (a, £ + 1, 7, *)
+ (« — 7)^ (« — 1, A 7, 2;) = 0. (5
From 3), 5) let us eliminate F (a, /3 + 1, 7, z), getting
(« — 1 — (7 — /3 — 1)»)^(a, /3, 7, x) + (7 — a)F(a — 1, /3, 7, 2;)
+ (1 — 7)(1 — xjF(a, /3,7-1,*) = 0. (6
In 1) let us replace « by a — 1 and 7 by 7 + 1; we get
(7 — a + 1 ~)F(a — 1, /3, 7 + 1, 2;) + (a — 1 )F(a, /3, 7 + 1, 2;)
- 7^ 7 (cc - 1, /3, 7, 2;) =0. (a)
In 6) let us replace 7 by 7 + 1 ; we get
(«-1—(7 —/3)2-)F(a, A 7+1, 2^) + (7 +1 — a)F(a — 1, /3, 7 + I, x')
-y(\ — x)F(a,[3,y,x') = Q. (b)
Subtracting (b) from (a), eliminates ,F(« — 1, /3, 7+ 1, 2:) and
gives
7(1 — x^F(a/3yx} — yF(a — 1, /3, 7, 2;)
+ (7 — fi)xF(a, A 7 + 1» *) = 0. (7
From 6), 7) we can eliminate F(u — 1, /3, 7, #), getting
7|7 — 1 +(« + /3 +1 — 2 7)2v\F(a, A 7, *)
+ (7 — a) (7 — ¡3)xF(ct, A 7 + 1, 2;)
+ 7(l-7)(l-i)i T (« 1 A7-l+)=0- (8
In this manner we may proceed, getting the remaining seven.
188. Conjugate Functions. From the relations between con
tiguous functions we see that a linear relation exists between any
three functions
F(u, A 7> x) F(a’, /3', 7', x) F(a", A', 7", x)
whose corresponding parameters differ only by integers. Such
functions are called conjugate.