where are positive integers and being co-prime.
Find
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Using the Maclaurin series expansion for tan − 1 x we define f ( a ) = ∫ 0 1 x a tan − 1 x d x = n = 0 ∑ ∞ ( 2 n + 1 ) ( 2 n + a + 2 ) ( − 1 ) n , a ≥ − 1 , so that f ( j ) ( a ) = ( − 1 ) j j ! n = 0 ∑ ∞ ( 2 n + 1 ) ( 2 n + a + 2 ) j + 1 ( − 1 ) n , j ≥ 0 , (all these series converge absolutely and uniformly for a ≥ − 1 , so the term-by-term differentiation is justified). Thus f ′ ′ ( 0 ) = 2 n = 0 ∑ ∞ ( 2 n + 1 ) ( 2 n + 2 ) 3 ( − 1 ) n f ′ ′ ′ ( 0 ) = − 6 n = 0 ∑ ∞ ( 2 n + 1 ) ( 2 n + 2 ) 4 ( − 1 ) n and so ∫ 0 1 tan − 1 x [ ( ln x ) 3 + 3 ( ln x ) 2 ] d x = = = = = = = f ′ ′ ′ ( 0 ) + 3 f ′ ′ ( 0 ) 6 n = 0 ∑ ∞ [ ( 2 n + 1 ) ( 2 n + 2 ) 3 ( − 1 ) n − ( 2 n + 1 ) ( 2 n + 2 ) 4 ( − 1 ) n ] 6 n = 0 ∑ ∞ ( 2 n + 1 ) ( 2 n + 2 ) 4 ( − 1 ) n [ ( 2 n + 2 ) − 1 ] 6 n = 0 ∑ ∞ ( 2 n + 2 ) 4 ( − 1 ) n = 8 3 n = 0 ∑ ∞ ( n + 1 ) 4 ( − 1 ) n 8 3 [ n = 1 ∑ ∞ n 4 1 − 2 n = 1 ∑ ∞ ( 2 n ) 4 1 ] 8 3 [ ζ ( 4 ) − 8 1 ζ ( 4 ) ] = 6 4 2 1 ζ ( 4 ) 1 9 2 0 7 π 4 , making the answer 7 + 1 9 2 0 + 4 = 1 9 3 1 .