In this post We will proof the following integrals related to the Catalan´s Constant . The proofs are based on the following paper: Representations of Catalan’s constant, David Bradley, 2001 (1) Proof: (2) Proof: (3) Proof: (4) Proof: By equation (A.7) of the appendix we have Than, we can rewrite our itegral as Equating (3) and (4) we conclude that (5) Letting in (5) we obtain (6) We can Integrate by part (6) to get And from (6) we conclude that (7) Now, let in (7) Ans from (7) we conclude that (8) Appendix (A.1) Proof: Recall the addition formulas of sine and cosine (see here ) (A.2) (A.3) Examples: Another two examples that will be useful in the next proof (A.4) Proof: Recall the double angle formulas (see here ): (A.5) (A.6) Than (A.7) Proof: Reference Representations of Catalan’s constant, David Bradley, 2001