2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/168070We prove some fundamental properties of mu-differentiable functions. A new notion of local minimizer and maximizer is introduced and several extremum conditions are formulated using the language of nonstandard analysis.Accepted (18/June/2008) for International Journal of Applied Mathematics & Statistics (IJAMAS)Classical Analysis and ODEs26E35; 26E05; 26A24text