f(x-1)是奇函数
f(-x-1)=-f(x-1)
f(x)是偶函数
f(-x)=f(x)
f(9)=f(-9)=f(-8-1)
=-f(8-1)
=-f(7)
=-f(-7)
=-f(-6-1)
=f(6-1)
=f(5)
=f(-5)
=f(-4-1)
=-f(4-1)
=-f(3)
=-f(-3)
=-f(-2-1)
=f(2-1)
=f(1)
=9