26.已知在△ABC中,∠ABC=90°,AB=1,BC=2;
(1)現(xiàn)將△ABC繞點A順時針旋轉(zhuǎn)得到△ADE,
(i)如圖1,當(dāng)點D落在AC上時,則CD=
.
(ii)如圖2,在旋轉(zhuǎn)過程,連結(jié)CE,BD,試探究CE,BD的數(shù)量關(guān)系,并說明理由;
(2)如圖3,延長AB至點D,使BD=4,連接CD;現(xiàn)將△ABC繞點B順時針旋轉(zhuǎn)得到△A′B′C′,A′C′所在的直線與直線BC交于點P,與線段CD交于點Q,當(dāng)△CPQ是以PQ為腰的等腰三角形時,求CF的長.