Digital Library of Mathematical Functions
The Gamma Function -- Integrals

Integrals

1 2 π c - c + Γ ( s + a ) Γ ( b - s ) z - s s = Γ ( a + b ) z a ( 1 + z ) a + b
( a + b ) > 0 , - a < c < b , | ph z | < π .
1 2 π - | Γ ( a + t ) | 2 ( 2 b - π ) t t = Γ ( 2 a ) ( 2 sin b ) 2 a
a > 0 , 0 < b < π .
Barnes's Beta Integral
1 2 π - Γ ( a + t ) Γ ( b + t ) Γ ( c - t ) Γ ( d - t ) t = Γ ( a + c ) Γ ( a + d ) Γ ( b + c ) Γ ( b + d ) Γ ( a + b + c + d )
a , b , c , d > 0
Ramanujan's Beta Integral
- t Γ ( a + t ) Γ ( b + t ) Γ ( c - t ) Γ ( d - t ) = Γ ( a + b + c + d - 3 ) Γ ( a + c - 1 ) Γ ( a + d - 1 ) Γ ( b + c - 1 ) Γ ( b + d - 1 )
( a + b + c + d ) > 3 .
de Branges-Wilson Beta Integral
1 4 π - k = 1 4 Γ ( a k + t ) Γ ( a k - t ) Γ ( 2 t ) Γ ( - 2 t ) t = 1 j < k 4 Γ ( a j + a k ) Γ ( a 1 + a 2 + a 3 + a 4 )
( a k ) > 0 , k = 1 , , 4 .