Let sA and s be the Sharpe ratio of portfolios A and B, respectively. Let TA and rB be the expected returs of these two portfolios, with standard deviation denoted by A and oB, respectively. Assume that through self financing portfolio A borrows (/oA-1) at risk free rate rf to leverage (or de-leverage) on portfolio A so that the risk for two portfolios are now the same (i.e., the leverage portfolio is long B/OA units of portfolio A and short (/0A-1) units of cash). . (a) Verify the leverage portfolio now has a risk of B (same as portfolio B) (b) Show that the excessive return of leveraged investment in portfolios A is sAB and that the expected return of the leveraged portfolio on A portiol thian the expected retun of pourtfo is larger than the expected return of portfolio B if sA> SB. This shows that the Sharpe ratio measures the efficiency of a portfolio