(1)∵E,F分别为棱BB1和DD1的中点,∴FD∥B1E,FD=B1E,
∴四边形FDEB1为平行四边形,∴DF∥FB1,DF?平面ADE,FB1?平面ADE,
∴FB1∥平面ADE,
又AD∥B1C1,AD?平面ADE,B1C1?平面ADE,∴B1C1∥平面ADE,
又FB1∩B1C1=B1,∴平面B1FC1∥平面ADE;
(2)连接EF、AF、A1F,A1E,
∴VA1?AEF=VE?A1AF=
×1 3
×AA1×AD×AB=1 2
×1×1×1=1 6
;1 6
(3)∵AH=
,动点H在底面ABCD内,∴点H的轨迹为1 2
圆弧,1 4
过G作GM⊥CD,垂足为M,∵MH≥MA-AH=
-
(
)2+12
3 4
=1 2
,3 4
又GH=
≥
GH2+MH2
=
12+(
)2
3 4
.5 4
∴GH长度的最小值为
.5 4