f(-x)=-f(x)
f(0)+f(0)=0
且f(1-x)=-f(x-1)
f(x+1)=-f(x-1)
f(x+2)=-f(x)
f(x+4)=f(x)
f(x+4n)=f(x)
f(2008)=f(0+4*502)=f(0)