We prove necessary optimality conditions, in the class of continuous
functions, for variational problems defined with Jumarie's modified
Riemann-Liouville derivative. The fractional basic problem of the calculus of
variations with free boundary conditions is considered, as well as problems
with isoperimetric and holonomic constraints.Comment: Submitted 13-Aug-2010; revised 24-Nov-2010; accepted 28-March-2011;
for publication in Computers and Mathematics with Application