y=1/2cos²x+√3/2sinxcosx+1 =1/4(1+cos2x)+√3/4*sin2x+1 =1/2(√3/2sin2x+1/2cos2x)+5/4 =1/2sin(2x+π/6)+5/4当2x+π/6=2kπ-π/2即x=kπ-π/3,k∈Z时，f(x)的最小值为1/2-5/4=-3/4x的集合为{x}x=kπ-π/3,k∈Z}
