26.如圖,△ABC是等腰直角三角形,∠ABC=45°,AB=AC,點(diǎn)D是AC上任意一點(diǎn),點(diǎn)H是射線BC上一點(diǎn),連接BD,AH.
(1)如圖1,當(dāng)點(diǎn)H在線段BC上時(shí),若AH⊥BD,AB=3
,AH=
,求△AHC的面積;
(2)如圖2,將線段BD繞點(diǎn)D順時(shí)針旋轉(zhuǎn)90°得到線段DE,連接CE,取CE中點(diǎn)M,連接DM.求證:AD=
DM;
(3)如圖3,連接DH,將△ADH沿AH翻折得到△AD'H,連接BD',若點(diǎn)F是BD'的中點(diǎn),且∠ABD=30°,AD=2,當(dāng)CF取最小值時(shí),求
的值.