证明:
∵CD⊥AB,BE⊥AC
∴∠ADC=∠AEB=90
∵AB=AC,∠BAE=∠CAD
∴△ABE≌△ACD (AAS)
∴AD=AE
2、AO⊥BC
证明:
∵∠ADC=∠AEB=90,AD=AE,AO=AO
∴△AOD≌△AOE (HL)
∴∠BAO=∠CAO
∴AO平分∠BAC
∵AB=AC
证明:
∵CD⊥AB,BE⊥AC
∴∠ADC=∠AEB=90
∵AB=AC,∠BAE=∠CAD
∴△ABE≌△ACD (AAS)
∴AD=AE
2、AO⊥BC
证明:
∵∠ADC=∠AEB=90,AD=AE,AO=AO
∴△AOD≌△AOE (HL)
∴∠BAO=∠CAO
∴AO平分∠BAC
∵AB=AC