令x=0
f(2)=-f(0)
f(0)=-f(2)
令x=-2
f(0)=-f(-2)
因此f(2)=f(-2)
又函数为奇函数,f(2)=-f(-2),f(-2)=-f(-2) 2f(-2)=0 f(-2)=0
f(2)=-f(-2)=0
f(6)=f(4+2)=-f(4)=-f(2+2)=f(2)=0