PLEASE HELP!!

Financial Mathematics question!

If we are only investing in assets 2 and 3, does this mean that the original constraints:

x1+x2+x3=1 , x1m1+x2m2+x3m3 = = 4 (that we would use for part (ii) just become:

x2+x3=1 and x2m2+x3m3 = = 4 (for part (i)) and then solve as normal?

Problem 5* Consider a market which consists of 3 assets, labelled 1,2,3. Suppose that the assets have a mean return vector m = (mi, m2, m3) = (1,1,2) and the covariance matrix /3 1 0 1 0 1 1 1 2 (i) Assume that we only invest in assets 2 and 3. Write down the min-var matrix problem and find the min-var efficient portfolio with mean return u = 3 (ii) Now, assume that we invest in the whole market. Write down the min var matrix problem and find the min-var efficient portfolio with mean return = 4. Problem 5* Consider a market which consists of 3 assets, labelled 1,2,3. Suppose that the assets have a mean return vector m = (mi, m2, m3) = (1,1,2) and the covariance matrix /3 1 0 1 0 1 1 1 2 (i) Assume that we only invest in assets 2 and 3. Write down the min-var matrix problem and find the min-var efficient portfolio with mean return u = 3 (ii) Now, assume that we invest in the whole market. Write down the min var matrix problem and find the min-var efficient portfolio with mean return = 4