I am doing some revision questions on my Portfolio Theory module, and have come across the following question:
Consider an investor who has constructed a risky portfolio from N securities. The investment opportunity set is described by the equation:
$\sigma^2 = 10 - 5{\times}E(r) + 0.5\times(E(r))^2$
Find the minimum variance portfolio.
I can't find any info in my notes, but my intuition says differentiate, set to zero and rearrange for E(r)?