f(x+2) = (1+f(x))/(1-f(x));
f(x+4) = (1+f(x+2))/(1-f(x+2)) = -1/f(x);
f(x+8) = f(x);
所以f(x)是以8为周期的周期函数.
f(2002) = f(250*8 +2) = f(2) = 2;
f(x+2) = (1+f(x))/(1-f(x));
f(x+4) = (1+f(x+2))/(1-f(x+2)) = -1/f(x);
f(x+8) = f(x);
所以f(x)是以8为周期的周期函数.
f(2002) = f(250*8 +2) = f(2) = 2;