23.在△ABC中,CA=CB,∠ACB=α,D為△ABC內(nèi)一點(diǎn),將△CAD繞點(diǎn)C按逆時(shí)針?lè)较蛐D(zhuǎn)角α得到△CBE,點(diǎn)A,D的對(duì)應(yīng)點(diǎn)分別為點(diǎn)B,E.
(1)如圖1,若A,D,E三點(diǎn)在同一直線上,則∠CDE=
(用含α的代數(shù)式表示);
(2)如圖2,若A,D,E三點(diǎn)在同直線上,α=60°,過(guò)點(diǎn)C作CF⊥AE于點(diǎn)F,然后探究線段CF,AE,BE之間的數(shù)量關(guān)系,并證明你的結(jié)論;
(3)圖3中,連接AE,若α=60°,CA=2
,CD=2,將△DCE繞點(diǎn)C旋轉(zhuǎn)一周,當(dāng)∠AEC=60°時(shí),BE=
.