显然1-f(x)≠0
所以 f(x+2) = [1+f(x)]/[1-f(x)]
另有 f(x) = [1+f(x-2)]/[1-f(x-2)]
将下式代入上式,解得f(x+2) = -1/f(x-2)
而f(x+6) = -1/f(x+2)
得到f(x+6)=f(x-2),以8为周期
f(2013)=f(8*251+5)=f(3)
由 f(x+2) = [1+f(x)]/[1-f(x)]得:
f(3)=f(1+2)=[1+f(1)]/[1-f(1)]=(1+2)/(1-2)=-3
显然1-f(x)≠0
所以 f(x+2) = [1+f(x)]/[1-f(x)]
另有 f(x) = [1+f(x-2)]/[1-f(x-2)]
将下式代入上式,解得f(x+2) = -1/f(x-2)
而f(x+6) = -1/f(x+2)
得到f(x+6)=f(x-2),以8为周期
f(2013)=f(8*251+5)=f(3)
由 f(x+2) = [1+f(x)]/[1-f(x)]得:
f(3)=f(1+2)=[1+f(1)]/[1-f(1)]=(1+2)/(1-2)=-3