1.f（π）=f（π-4）=- f（4- π）=-（4-π+1）=π - 5
2.f(x+2)[1-f(x)]=1+f(x)
f(x+2)=[1+f(x)]/[1- f(x)]
={1+ [1+f(x-2)]/[1- f(x-2)]}/{1- [1+f(x-2)]/[1- f(x-2)]}
=[1- f(x-2)+1+f(x-2)]/[1-f(x-2)- 1- f(x-2)]
=- 1/f(x-2)
f(x)=- 1/f(x+4)=f(x+8)
f(2008)=f(0+251*8)=f(0)=2008
3.f(x)=f(x-1)+f(x+1)
f(x+1)=f(x)+f(x+2)
上下兩個(gè)式子相加：f(x-1)+f(x+2)=0
f(x)=- f(x+3)=f(x+6)
f(69)=f(3+11*6)=f(3)=- f(0)=- 6
4.a=f(log½2)=f(-1)=f(1)=f(3)
b=f(-4)=f(4)
c=f(-π)=f(8-π )
因?yàn)椋?f(8-π)
即：a>b>c