y = f(x)f(x) = [(x^2 - 3x + 2)/(x^2 - x - 2)]^2= { [(x - 1)*(x - 2)]/[(x + 1)(x - 2)] }^2由于 x ≠ 2 所以有f(x) = [(x - 1)/(x + 1)]^2 另外,x ≥ 1 所以可展开：√y = (x - 1)/(x + 1)√y*(x + 1) = x - 1(...