1 The minimum variance portfolio problem min Er st. ex=1, px= R where the target return must be achieved exactly, short-selling is allowed, and the covariance matrix is assumed to be positive definite. Here, e is the n-dimensional vector of all ones. Assume that there are at least two assets whose mean returns are not equal to each other. Denote three scalars A=ee, B=e and CE 2. Prove that for every R, the point (on, R) lies on the hyperbola (o, R)-plane. - (R-B/A) (C/A-BA) -1 in the (6 marks) 3. Explain why the efficient frontier is produced by all portfolios that have the value of R being Re[.). (3 marks)