fractional derivative introduced and established by Katugampola [arxiv: 1410.6535 v1] and
Khalil et al.[J. Comput. Appl. Math. 264 (2014) 65-70]. Among other things we show that
each function $ f $ defined on $(a, b) $, $ a> 0$ has a conformable fractional derivative
(CFD) if and only if it has a classical first derivative. At the end of the paper, we prove the
Rolle's, Cauchy, Lagrange's and Darboux's theorem in the context of Conformable …