Y = sin(x+π/3)sin(x+π/2)
= sin(x+π/3)cosx
= 1/2sin(x+π/3+x) + 1/2sin(x+π/3-x) 【积化和差公式】
= 1/2sin(2x+π/3) + 1/2sin(π/3)
最小正周期 = 2π/2 = π