Theorem: Gaussian Hypergeometric Function Difference Equation/Formulation 4

{{begin-eqn}}
{{eqn | l = \map F {a + 1, b, c; x} - \map F {a, b, c; x}
      | r = \frac {b x } c \map F {a + 1, b + 1, c + 1; x}
}}
{{end-eqn}}

Proof:
{{begin-eqn}}
{{eqn | l = \map F {a + 1, b, c; x}
      | r = \sum_{n \mathop = 0}^\infty \frac {\paren {a + 1}^{\overline n} b^{\overline n} } {c^{\overline n} n!} x^n
      | c = {{Defof|Gaussian Hypergeometric Function}}
}}
{{eqn | r = 1 + \frac {\paren {a + 1} b } c x + \cdots + \frac {\map \Gamma {a + 1 + n} \map \Gamma {b + n} \map \Gamma c } {\map \Gamma {c + n} \map \Gamma {a + 1 } \map \Gamma b } \frac {x^n} {n!} + \cdots
      | c = {{Defof|Rising Factorial}}
}}
{{eqn | r = 1 + \frac {\paren {a + 1} b } c x + \cdots + \frac {\paren {a + n} \map \Gamma {a + n} \map \Gamma {b + n} \map \Gamma c } { \map \Gamma {c + n} a \map \Gamma a \map \Gamma b } \frac {x^n} {n!} + \cdots
      | c = Gamma Difference Equation
}}
{{eqn | r = 1 + \frac {\paren {a + 1} b } c x + \cdots + \frac {\paren {a + n} } a \frac {\map \Gamma {a + n} \map \Gamma {b + n} \map \Gamma c } {\map \Gamma {c + n} \map \Gamma a \map \Gamma b } \frac {x^n} {n!} + \cdots
      | c = 
}}
{{eqn | l = \map F {a, b, c; x}
      | r = \sum_{n \mathop = 0}^\infty \frac {a^{\overline n} b^{\overline n} } {c^{\overline n} n!} x^n
      | c = {{Defof|Gaussian Hypergeometric Function}}
}}
{{eqn | r = 1 + \frac {a b } {c } x + \cdots + \frac {\map \Gamma {a + n} \map \Gamma {b + n} \map \Gamma {c } } {\map \Gamma {c + n} \map \Gamma {a } \map \Gamma {b } } \frac {x^n} {n!} + \cdots
      | c = {{Defof|Rising Factorial}}
}}
{{eqn | ll= \leadsto
      | l = \map F {a + 1, b, c; x}
      | r = 1 + \frac {\paren {a + 1} b } c x + \cdots + \frac {\paren {a + n} } a \frac {\map \Gamma {a + n} \map \Gamma {b + n} \map \Gamma c } {\map \Gamma {c + n} \map \Gamma a \map \Gamma b } \frac {x^n} {n!} + \cdots
      | c = 
}}
{{eqn | lo = -
      | l = \map F {a, b, c; x}
      | r = 1 + \frac {a b } {c } x + \cdots + \frac {\map \Gamma {a + n} \map \Gamma {b + n} \map \Gamma {c } } {\map \Gamma {c + n} \map \Gamma {a } \map \Gamma {b } } \frac {x^n} {n!} + \cdots
      | c = 
}}
{{eqn | r = \paren { \paren {a + 1} - a  } \frac b c x + \cdots + \paren { \frac {\paren {a + n} } a - 1} \frac {\map \Gamma {a + n} \map \Gamma {b + n} \map \Gamma {c } } {\map \Gamma {c + n} \map \Gamma {a } \map \Gamma {b } } \frac {x^n} {n!} + \cdots
      | c = 
}}
{{eqn | r = \frac b c x + \cdots + \paren { \frac n a } \frac {\map \Gamma {a + n} \map \Gamma {b + n} \map \Gamma {c } } {\map \Gamma {c + n} \map \Gamma {a } \map \Gamma {b } } \frac {x^n} {n!} + \cdots
      | c = 
}}
{{eqn | r = \frac b c x + \cdots + \paren { \frac n a } \frac {\map \Gamma {a + n} \map \Gamma {b + n} \map \Gamma {c } } {\map \Gamma {c + n} \map \Gamma {a } \map \Gamma {b } } \times \frac {b c} {b c} \times x \times \frac {x^{n - 1} } {n!} + \cdots
      | c = multiplying by $1$ and factoring out an $x$
}}
{{eqn | r = \frac b c x + \cdots + \frac b c x \frac {\map \Gamma {a + n} \map \Gamma {b + n} \map \Gamma {c + 1 } } {\map \Gamma {c + n} \map \Gamma {a + 1 } \map \Gamma {b + 1 } } \frac {x^{n - 1} } {\paren {n - 1}!} + \cdots
      | c = Gamma Difference Equation and canceling an $n$
}}
{{eqn | r = \frac b c x + \cdots + \frac b c x \frac {\map \Gamma {a + 1 + n} \map \Gamma {b + 1 + n} \map \Gamma {c + 1 } } {\map \Gamma {c + 1 + n} \map \Gamma {a + 1 } \map \Gamma {b + 1 } } \frac {x^n } {n!} + \cdots
      | c = $n \to n + 1$
}}
{{eqn | r = \frac {b x } c  \sum_{n \mathop = 0}^\infty \frac {\paren {a + 1}^{\overline n} \paren {b + 1}^{\overline n} } {\paren {c + 1}^{\overline n} n!} x^n
      | c = 
}}
{{eqn | r = \frac {b x } c \map F {a + 1, b + 1, c + 1; x}
      | c = {{Defof|Gaussian Hypergeometric Function}}
}}
{{end-eqn}}
{{qed}}