\[Рисунок\ в\ учебнике.\]
\[\angle AOB = \angle BOC = \angle COD =\]
\[= \angle DOE = \angle EOF.\]
\[1)\ Луч\ OB - биссектриса\ \angle AOC:\]
\[\angle AOB = \angle BOC.\]
\[Луч\ OE - биссектриса\ \angle DOF:\]
\[\angle DOE = \angle EOF.\]
\[Луч\ OD - биссектриса\ \angle BOF:\]
\[\angle BOD = \angle BOC + \angle COD = 2\angle AOB;\]
\[\angle DOF = \angle DOE + \angle EOF = 2\angle AOB;\]
\[\angle BOD = \angle DOF.\]
\[Ответ:\ \ OB;\ OE;\ OD.\]
\[2)\ Луч\ OC - биссектриса\ \angle BOD:\]
\[\angle BOC = \angle COD.\]
\[Луч\ OC - биссектриса\ \angle AOE:\]
\[\angle AOC = \angle AOB + \angle BOC = 2\angle AOB;\]
\[\angle COE = \angle COD + \angle DOE = 2\angle AOB;\]
\[\angle AOC = \angle COE.\]
\[Ответ:\ \ \angle BOD;\ \angle AOE.\]