Let f(x) = kx(1 - x) and assume that k > 0, show that the

Let f(x) = kx(1 - x) and assume that k > 0, show that the values of a and b for which f(a) = b and f(b) = a are given by the formulas: a = (1 + k + akar((k - 3)(k + 1)))/2k and b = (1 + k - akar((k - 3)(k + 1)))/2k