Question

如图,在正方形ABCD中,M是AB上一点,且DM=BC+BM,N是BC的中点.求证：DN平分∠CDM

Answer 1

参考：延长AB和DN相交于点平P..先证△NBP≌△NCD,再证明MP=MD,从而∠MDP＝∠P＝∠CDN.