第一象限{θ|2kπ<=θ<=π/2+2kπ,k属于Z}第二象限{θ|π/2+2kπ<=θ<=π+2kπ,k属于z}第三象限{θ|π+2kπ<=θ<=3π/2+2kπ,k属于z}第四象限{θ|3π/2+2kπ<=θ<=2π+2kπ,k属于z}
