3.如圖,已知等腰三角形ABC中,∠BAC=30°,AB=AC,∠PAB=α,作點(diǎn)B關(guān)于直線AP的對(duì)稱(chēng)點(diǎn)為點(diǎn)D,連接AD,連接BD交AP于點(diǎn)G,連接CD交AP于點(diǎn)E,交AB于點(diǎn)F.
(1)如圖(1)當(dāng)α=15°時(shí),
①按要求畫(huà)出圖形,
②求出∠ACD的度數(shù),
③探究DE與BF的倍數(shù)關(guān)系并加以證明;
(2)在直線AP繞點(diǎn)A順時(shí)針旋轉(zhuǎn)的過(guò)程中(0°<a<75°),當(dāng)△AEF為等腰三角形時(shí),利用下頁(yè)備用圖直接求出α的值為
.