T=2π/ω=2π/(顷行k/3)=6π/k,2/3则8π则k为26或27或28看看对不
2π/(k/3)=6π/k∈(2/3,3/4),即2/纤贺孝3<6π/k<3/4,拍弊得到8π
要是f(x)的2/3<告和T<3/4,因袜庆盯为T=2π/w,w=k/3所以2/3<6π/差磨k<3/4,8π