cos²(x+π/6)=3/4cos(x+π/6)=±√3/2所以x+π/6=2kπ±π/6或x+π/6=2kπ±7π/6所以x=2kπ-π/3或x=2kπ或x=2kπ+π或x=2kπ-4π/3所以集合是{x|x=2kπ-π/3或x=2kπ或x=2kπ+π或x=2kπ-4π/3,k∈Z}如果不懂...