∵OD⊥AB，OE⊥AC，AO ∠BAC，
∴OD=OE.？
∵∠ 1=∠2,
∴OB=OC.？
Rt△BDO and Rt△CEO
OD=OEOB=OC，
∴△DOB≌△EOC(HL)，
∴∠DBO=∠ECO，
∴∠ABC=∠ACB，
∴AB=AC.
∫OA segmentation ∠BAC,
∴AO⊥BC.
A. high school physics is very difficult. Now that my son is a sophomore, how can he learn high school physics well? Is there a better extracurricul