已知函数f(x)=sin(2x+π/6)+sin(2x-π/6)+cos2x+a(a∈R,a为常数)1、求f(x)的最小正周期2、求单调递增区间3、若x∈[0,π/2],f(x)的最小值是-2,求a的值

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已知函数f(x)=sin(2x+π/6)+sin(2x-π/6)+cos2x+a(a∈R,a为常数)1、求f(x)的最小正周期2、求单调递增区间3、若x∈[0,π/2],f(x)的最小值是-2,求a的值
已知函数f(x)=sin(2x+π/6)+sin(2x-π/6)+cos2x+a(a∈R,a为常数)
1、求f(x)的最小正周期
2、求单调递增区间
3、若x∈[0,π/2],f(x)的最小值是-2,求a的值

已知函数f(x)=sin(2x+π/6)+sin(2x-π/6)+cos2x+a(a∈R,a为常数)1、求f(x)的最小正周期2、求单调递增区间3、若x∈[0,π/2],f(x)的最小值是-2,求a的值
1.
f(x)=sin(2x+π/6)+sin(2x-π/6)+cos2x+a
=√3/2sin2x+1/2cos2x+√3/2sin2x-1/2cos2x+cos2x+a
=√3sin2x+cos2x+a
=2sin(2x+π/6)+a
所以f(x)的最小正周期2π/2=π
2.
sinx的单调递增区间[2kπ-π/2,2kπ+π/2]
所以2kπ-π/2

f(x)=sin(2x+π/6)+sin(2x-π/6)+cos2x+a
=2sin2xcosπ/6+cos2x+a
=2sin(2x+π/6)+a
1)T=π
2)sinx单调递增区间为[2kπ-1/2π,2kπ+1/2π]