Foran, James The symmetric and ordinary derivative. (English) Zbl 0376.26005 Real Anal. Exch. 2, 105-108 (1977). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 2 Documents MSC: 26A24 Differentiation (real functions of one variable): general theory, generalized derivatives, mean value theorems 26A27 Nondifferentiability (nondifferentiable functions, points of nondifferentiability), discontinuous derivatives PDF BibTeX XML Cite \textit{J. Foran}, Real Anal. Exch. 2, 105--108 (1977; Zbl 0376.26005) OpenURL