Studying for exams is an art. It is a subject in itself on which few books have been written.

One of the skills involved in studying for an exam is deciding what is important (and concentrating on those points) and what can be discarded (as it is unlikely to come up in the exam). Generally, the more experienced you are, the easier it is to reduce an entire course to a set of likely questions and their assumed knowledge, and get it right. Previous exams, main points, and the parts of the course the instructor concentrates on in the revision period can all be used to mould a draft of the upcoming examination.

I had one such exam on Partial Differential Equations at the end of the last semester. On the morning of the exam, I was skimming through my notes when I came across a concept I was deliberating on whether to study or not – d’Alembert’s solution to the one dimensional wave equation. It was present in my revision notes, but it was a very cumbersome proof that I couldn’t really be bothered to go through. So I cast it aside.

And guess what? About an hour later, I was staring at a question asking me to provide a solution to a one dimensional wave equation using d’Alembert’s solution. Out of 4 questions, it was an entire question on its own. I scribbled something pathetic in the top-left corner of the answer sheet and turned the page in the hope that I would be inspired to some level of genius when I had finished the other questions. I was not. In the end, I left the question blank. I had rolled the dice on D’Alembert and lost.

The moral of this story is there is no way to be certain of what’s coming up in an examination – study it all lest you fall prey to the D’Alembert Gamble.