2.如圖1,△ACB中,AB=CB,∠ABC=90°,點(diǎn)P在射線BC上(不與點(diǎn)B,點(diǎn)C重合),以AP為邊作△PAQ,使AP=AQ,∠PAQ=90°,QE⊥AB于點(diǎn)E.
(1)當(dāng)點(diǎn)P在線段BC上(不與點(diǎn)B,點(diǎn)C重合),求證:△PAB≌△AQE;
(2)在(1)的條件下,連接CQ交AB于點(diǎn)M,求
的值;
(3)如圖2,過(guò)點(diǎn)Q作QF⊥AQ于直線AB于點(diǎn)F,過(guò)點(diǎn)P作DP⊥AP交直線AC于點(diǎn)D,連接DF.則點(diǎn)P在運(yùn)動(dòng)過(guò)程中,線段DF、QF與DP有怎樣的數(shù)量關(guān)系?請(qǐng)說(shuō)明理由.