Hi Xenia, I hope my answers in the office hours were sufficient, but just to be clear in case someone else is reading this:
The matrix formula for the Tangency portfolio on the formula sheet applies to any set of assets, including 2.
The matrix formula for the variance of a portfolio on the formula sheet applies to any set of assets, including 2. Note also that expression using sums literally sums over the variance and covariance terms, which I suppose is the expression you are looking for.
From my experience, I would say there is a huge benefit to knowing things by heart and I am not asking you to learn by heart formulas that have little intuition. Compare, for instance, the optimal weight in one of the two assets in a two-asset portfolio vs the matrix formula for the tangency portfolio which is "just" expected return divided by variance in multivariate form.
Good luck.
M
The matrix formula for the Tangency portfolio on the formula sheet applies to any set of assets, including 2.
The matrix formula for the variance of a portfolio on the formula sheet applies to any set of assets, including 2. Note also that expression using sums literally sums over the variance and covariance terms, which I suppose is the expression you are looking for.
From my experience, I would say there is a huge benefit to knowing things by heart and I am not asking you to learn by heart formulas that have little intuition. Compare, for instance, the optimal weight in one of the two assets in a two-asset portfolio vs the matrix formula for the tangency portfolio which is "just" expected return divided by variance in multivariate form.
Good luck.
M