f(x)是奇函数则f(x)=-f(-x)又f(x+2)=f(x)a=f(6/5)=f(-4/5+2)=f(-4/5)=-f(4/5)=-lg(4/5)b=f(3/2)=f(-1/2+2)=f(-1/2)=-f(1/2)=-lg(1/2)c=f(5/2)=f(2+1/2)=f(1/2)=lg(1/2)-lg(1/2)>-lg(4/5)>lg(1/2)所以b>a>c