T=1
故f(11/2)=f(1/2)=f(-1/2)
当x∈(-1,0)时,f(x)=3x+1,
故f(-1/2)=-1/2
函数是奇函数故f(1/2)=-f(-1/2)
故f(1/2)=0
f(11/2)=0或-1/2