Entity["MathematicalFunction", "Sin"]["SeriesRepresentations"][[2]][
  x] // TraditionalForm

% // Activate

(* True *)

Entity["MathematicalFunction", "Sin"]["SeriesRepresentations"][[2]][
  x] // TraditionalForm

% // Activate

(* True *)

EDIT: For a cleaner display

Entity["MathematicalFunction", "Sin"]["SeriesRepresentations"][[2]][x] // 
  Activate[#, Except[Sum]] & // TraditionalForm