(Ⅰ)由已知,得f(x)=
sin2x+1 2
cos2x=1 2
sin(2x+
2
2
),π 4
∵ω=2,∴T=π,
则f(x)的最小正周期为π;
(Ⅱ)∵-
≤x≤π 8
,∴0≤2x+π 2
≤π 4
,5π 4
则当2x+
=π 4
时,即x=π 2
时,f(x)取得最大值π 8
;
2
2
当2x+
=π 4
时,即x=5π 4
时,f(x)取得最小值-π 2
.1 2