Resumen de Presenting the Straddle Lemma in an introductory Real Analysis course

A.A. Soares, A.L.C. Dos Santos

• In this article, we revisit the concept of strong differentiability of real functions of one variable, underlying the concept of differentiability. Our discussion is guided by the Straddle Lemma, which plays a key role in this context. The proofs of the results presented are designed to meet a young audience in mathematics, typical of students in a first course of Real Analysis or an honors-level Calculus course.