(1)f(x)=sin(2x+π/6)-cos(2x+π/3)+2cos²x
= sin2x cosπ/6+cos2x sinπ/6-[ cos2x cosπ/3- sin2x sinπ/3] +2cos²x
=√3 sin2x+2cos²x=√3 sin2x+1+cos2x
=2 sin(2x+π/6)+1,
f(π/12)=2sin(2*π/12+π/6)+1=√3+1.
(2)当2x+π/6 ∈[ -π/2+2kπ ,π/2+2kπ ] 函数fx单调递增
(3)f(x)的最大值是3,
此时2x+π/6=2kπ+π/2,x=kπ+π/6,k∈Z.