(1)CE=CF AC=BC ∠BCE=∠ACF=90°-∠ACE△ECB≌△FCA∴BE=AF ∠FAC=∠B=45°∠AFB=45°+45°=90°∴BE⊥AF (2)EG:FG=S△AEG:S△AFG=S△CEG:S△桥圆CFG∴EG:FG=S△纤消早AEC:S△AFC=S△AEC:S△BEC=AE:BE=2(3)n=1/毁雀√2=√2/2