f(π-x)=-f(x)f(2π-x)=f(x)=-f(π-x)=-[-f(-x)]=f(-x)所以函数f(x)的周期为2πf(59π/11)=f(5π+4π/11)=f(π+4π/11)=-f(-4π/11)=-16π²/121
f(59π/11)=f(4π+15π/11)=f(15π/11)=f(π+4π/11)=-f(4π/11)=-(4π/11)^2=-16π^2/121