f(x+1)=-f(x)=f(-x)
当x=0 f(1)=f(0)
x=1 f(2)=f(-1)=-f(1)=f(0)
x=2.f(2)=f(0)
又奇函数在x=0有定义.f(0)=0
所以
f(1)+f(2)+f(3)+f(4)+f(5)+f(6)+f(7)
=7f(0)
=0
f(x+1)=-f(x)=f(-x)
当x=0 f(1)=f(0)
x=1 f(2)=f(-1)=-f(1)=f(0)
x=2.f(2)=f(0)
又奇函数在x=0有定义.f(0)=0
所以
f(1)+f(2)+f(3)+f(4)+f(5)+f(6)+f(7)
=7f(0)
=0