2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/56775We discuss the function wt(x) defined via the implicit equation wt(x)*tan[wt(x)]=x which appears in certain quantum mechanical and field theoretic applications. We investigate its analytic structure, develop series expansions for both small and large x, and provide various techniques for its numerical evaluation in the complex plane.24 pages, 10 EPS figures, corrected typosMathematical PhysicsHigh Energy Physics - TheoryComplex VariablesQuantum Physics33E99 (Primary) 39B32, 81Q05, 30F99, 30B10 (Secondary)text