因为单调递减,所以2kπ《π/3-x/2《2kπ+π
2kπ-π/3《-x/2《2kπ+2π/3
4kπ-2π/3《-x《4kπ+4π/3
所以4kπ-4π/3《-x《4kπ+2π/3
周期T=2π/w,已知w=1/2,所以T=4π
从递减区间也能看出
因为单调递减,所以2kπ《π/3-x/2《2kπ+π
2kπ-π/3《-x/2《2kπ+2π/3
4kπ-2π/3《-x《4kπ+4π/3
所以4kπ-4π/3《-x《4kπ+2π/3
周期T=2π/w,已知w=1/2,所以T=4π
从递减区间也能看出