Investment Portfolio. Consider once again, the investor in Example 4.3,4 on page 200
trying to choose a portfolio with $ 100,000 to invest. We shall make the same assumptions
about the returns on the two stocks except that now we will suppose that the correlation
between the two returns R1 and R2 is -0.3, reflecting a belief that the two stocks lend to
react in opposite ways to common market forces. The variance of a portfolio of s1 shares
of the first stock, s2 shares of the second stock, and s; dollars invested at 3.6% is now