Evaluate :
The format of the solution is as give below :
Submit your answer as if and are positive integers.
Clarifications :
denotes Euler–Mascheroni constant
denotes Digamma function
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ψ ( 1 + z ) = − γ + ∫ 0 1 1 − x 1 − x z d x
Putting z = 2 1
ψ ( 2 3 ) = − γ + ∫ 0 1 1 − x 1 − x d x = − γ + ∫ 0 1 1 + x 1 d x
Put x = t 2 ⟶ d x = 2 t d t
∴ ψ ( 2 3 ) = − γ + 2 ∫ 0 1 1 + t t d t
ψ ( 2 3 ) = − γ + 2 ∫ 0 1 1 d t − 2 ∫ 0 1 1 + t 1 d t
ψ ( 2 3 ) = − γ + [ 2 t ] 0 1 − [ 2 ln ( 1 + t ) ] 0 1
ψ ( 2 3 ) = − γ + 2 − 2 ln ( 2 )
ψ ( 2 3 ) = − γ + 2 − ln ( 4 )
A + B = 2 + 4 = 6