(Yield curve modelling) Consider a binomial model of the yield curve over 3 years where y0,1 = 4%. The probability of an up movement in 1-period forward rates for year t = 2, 3 is Pt = 0.25 + 0.2t, and 1-period forward rates can go up by a factor of u = 1.5 or down by a factor of d = 0.75. Calculate the zero-coupon bond yield curve and the implied 1-period forward rates embedded in this yield curve.