如图,△ABC中,AB=AC,BD、CE分别为△ABC的中线.求证:BD=CE.证明:∵BD、CE分别为△ABC的中线,∴AE= 1 2 AB,AD= 1 2 AC,∵AB=AC,∴AD=AE,在△ABD与△ACE中 AD=AE ① ② ,①∠A=∠A,②AB=AC,∴△ABD≌△ACE( SAS),∴BD=CE.故答案为:BD=CE; 1 2 AC;AD=AE;∠A=∠A,AB=AC;SAS.