Consider three assets, which are labelled as X, Y and Z. The variances of the three assets are respectively 0.26, 0.29, and 0.38. The correlation between assets X and Y is 0.6, between X and Z the correlation is 0.5, and the correlation between assets Y and Z is 0.83. What portfolio will produce the minimum variance if there are no constraints on the weights of the portfolio? What is the variance of that portfolio? Repeat the previous two parts of this question if the investor cannot short-sell any of the securities?