(* Authored with Mathematica 10.0 *)

SetDirectory[NotebookDirectory[]]

p = Plot[{Cos[x],Cos[(7/3)x]}, {x,0,3.5 Pi}, PlotStyle -> {{Darker[Blue], Thick},{Darker[Green], Dashed,Thick}}, LabelStyle->{FontFamily->"Times", FontSize -> 11},AspectRatio->0.3]

Export["mathematica-example.pdf", p]

AbsoluteFileName[%]