【導讀】A.4=a12B.a(chǎn)3·a5=a15C.a(chǎn)2+a2=a4D.a(chǎn)6÷a2=a3. 4.如圖,△ABC中,∠C=90°,∠BAC=60°,AD是角平分線,若BD=8,則。①AC=AE;②∠FAB=∠EAB;③EF=BC;④∠EAB=∠FAC,下列結(jié)論:①△ABE≌△ACD②△ABD≌△ACE③∠DAE=40°在圖中畫出與△ABC關于直線l成軸對稱的△A′B′C′;在直線l上找一點P,使PB+PC的長最短.21.(7分)如圖,在△ABC中,延長AC至點D,使CD=BC,連接BD,