(Ⅰ)∵f(x)=sinxcosx-cos2x+1
=
sin2x-1 2
+11+cos2x 2
=
sin2x-1 2
cos2x+1 2
1 2
=
sin(2x-
2
2
)+π 4
,1 2
∴函数f(x)的最小正周期为T=
=π.2π 2
(Ⅱ)∵x∈[-
,0],π 2
∴-
≤2x-5π 4
≤-π 4
.π 4
∴-1≤sin(2x-
)≤π 4
,
2
2
∴
≤?
+1
2
2
sin(2x-
2
2
)+π 4
≤1,1 2
即
≤f(x)≤1;?
+1
2
2
当2x-
=-π 4
时,即x=-π 2
时,函数f(x)取到最小值π 8
,?
+1
2
2
当2x-
=-π 4
,即x=-5π 4
时,函数f(x)取到最大值1.π 2