∫ 0 ∞ 1 + e x x ln x d x = B 1 π C − π D ln A + G π E ln F + I π H ln π
The equation above holds true for positive integers B , C , D , F , G , H and I such that F is minimized.
Find B + C + D + E + F + G + H + I .
Notation : A denotes the Glaisher–Kinkelin constant , A ≈ 1 . 2 8 2 4 .
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Problem Loading...
Note Loading...
Set Loading...
We know , − L i s ( − 1 ) = Γ ( s ) 1 ∫ 0 ∞ e x + 1 x s − 1 d x
So if G ( s ) = ∫ 0 ∞ e x + 1 x s − 1 d x then our target integral is G ′ ( 2 )
G ( s ) = − L i s ( − 1 ) Γ ( s ) = η ( s ) Γ ( s ) , Since by definition of polygarithm we see − L i s ( − 1 ) = n = 1 ∑ ∞ n s ( − 1 ) n − 1 = η ( s )
Since η ( s ) = ( 1 − 2 1 − s ) ζ ( s ) & Γ ′ ( s ) = Γ ( s ) ψ 0 ( s ) = Γ ( s ) ( H s − 1 − γ ) we have,
G ′ ( 2 ) = Γ ( 2 ) η ′ ( 2 ) + η ( 2 ) Γ ′ ( 2 ) = η ′ ( 2 ) + 1 2 π 2 ( 1 − γ )
η ′ ( s ) = ζ ′ ( s ) ( 1 − 2 1 − s ) + 2 1 − s ln 2 ζ ( s )
η ′ ( 2 ) = 1 2 π 2 γ + 1 2 π 2 ln π + 6 π 2 ln 2 − π 2 ln A
So we have G ′ ( 2 ) = 1 2 π 2 + 1 2 π 2 ln π + 6 π 2 ln 2 − π 2 ln A
So the answer is : 1 2 + 2 + 2 + 1 2 + 2 + 2 + 6 + 2 = 4 0