Taylor's series expansions for even powers of inverse cosine function and series representations for powers of Pi

In the paper, via series expansions of composite functions of the (hyperbolic) sine and cosine functions with the inverse sine and cosine functions respectively, the author establishes Taylor's series expansions of even powers of the inverse (hyperbolic) cosine function in terms of the Stirling numbers of the first kind, recovers series expansions of powers of the inverse (hyperbolic) sine function in terms of the Stirling numbers of the first kind, derives several combinatorial identities involving the Stirling numbers of the first kind, and presents several series representations of the circular constant Pi and its (even) powers.