25.【問(wèn)題情境】:如圖1,點(diǎn)E為正方形ABCD內(nèi)一點(diǎn),AE=2,BE=4,∠AEB=90°,將直角三角形ABE繞點(diǎn)A逆時(shí)針?lè)较蛐D(zhuǎn)α度(0≤α≤180°)點(diǎn)B、E的對(duì)應(yīng)點(diǎn)分別為點(diǎn)B′、E′.
【問(wèn)題解決】:
(1)如圖2,在旋轉(zhuǎn)的過(guò)程中,點(diǎn)B′落在了AC上,求此時(shí)CB′的長(zhǎng);
(2)若α=90°,如圖3,得到△ADE′(此時(shí)B′與D重合),延長(zhǎng)BE交DE′于點(diǎn)F,
①試判斷四邊形AEFE′的形狀,并說(shuō)明理由;
②連接CE,求CE的長(zhǎng);
(3)在直角三角形ABE繞點(diǎn)A逆時(shí)針?lè)较蛐D(zhuǎn)過(guò)程中,直接寫(xiě)出線段CE′長(zhǎng)度的取值范圍.