3.已知點(diǎn)E在正方形ABCD的對(duì)角線AC上,正方形AFEG與正方形ABCD有公共點(diǎn)A.
(1)如圖1,當(dāng)點(diǎn)G在AD上,F(xiàn)在AB上,則
=
;
(2)將正方形AFEG繞A點(diǎn)逆時(shí)針方向旋轉(zhuǎn)α(0°<α≤90°),如圖2,請(qǐng)求出
的值;
(3)若
,AG=1,將正方形AFEG繞A逆時(shí)針方向旋轉(zhuǎn)(0°<α≤360°),當(dāng)C,G,E三點(diǎn)共線時(shí),請(qǐng)直接寫出DG的長度.