∵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