Don't know about everyone else, but finding the equation of the efficient frontier in the presence of a risk-free asset in S2004,10(iv) seemed very hard. The examiner's solution uses a parameteric version of the equation, which in the end seems the easiest way to do it...working with it in the form V_p = f(E_p) seemed near impossible... strange how apparently easy questions can be really painful.
And for only 4 marks. The type of question I would just skip in an exam and come back to if there is time left at the end. (Which luckily there usually isn't). See-ya. Erik