)cos(x+
)+2
cos2(x+
)-
,α为常数.(Ⅰ)求函数f(x)的周期;
(Ⅱ)若0≤α≤π时,求使函数f(x)为偶函数的α值.在线课程解:(Ⅰ)f(x)=sin(2x+α)+
[cos(2x+α)+1]-
=sin(2x+α)+
cos(2x+α)=2sin(2x+α+
)∴f(x)的周期T=
=π(Ⅱ)要使函数f(x)为偶函数,
只需α+
=kπ+
,(k∈Z)即α=kπ+
,(k∈Z)因为0≤α≤π,
所以α=
.分析:(Ⅰ)f(x)=sin(2x+α)+
[cos(2x+α)+1]-
=2 sin(2x+α+
),由此能求出f(x)的周期.(Ⅱ)要使函数f(x)为偶函数,只需α+
=kπ+
,(k∈Z)由此能求出α.点评:本题考查三角函数的综合运用,解题时要认真审题,仔细解答,注意三角函数的恒等变换.