Tavares, DinaAlmeida, RicardoTorres, Delfim F. M.2018-09-112018-09-112015-02-16http://hdl.handle.net/10400.8/3533We establish necessary optimality conditions for variational problems with a Lagrangian depending on a combined Caputo derivative of variable fractional order. The endpoint of the integral is free, and thus transversality conditions are proved. Several particular cases are considered illustrating the new results.engdynamic optimizationfractional calculusvariable fractional orderfractional calculus of variationsjournal article10.1080/02331934.2015.1010088