f(x)=1/2sinx+√3/2cosx=sin(x+π/3)
∴单调增区间(2kπ-5π/6,2kπ+π/6)
f(x)=sin(x+π/3)≥1/2
∴x+π/3∈[2kπ+π/6,2kπ+5π/6]
∴x∈[2kπ-π/6,2kπ-π/2]