f(x+1)=-f(x)
将x换成x+1
则f(x+2)=-f(x+1)
∴ f(x+2)=f(x)
∴ f(7/2)
=f(3/2+2)
=f(3/2)
=f(-1/2)
=-f(1/2) ∵ f(x)是奇函数
=-[2*(1/2)+1]
=-2