In November 1989 I passed the entry exams for the “Bachillerato Bilingüe”, aka the “Bilingual Bachelor”, a parallel study program that existed in my high school, and which gave access to the coveted “Baccalauréat International” degree; turns out my school was one of the few in Latin America that had that possibility, so there I went.
The entry exams were quite competitive, which is Latin for “difficult”. There were three of them; the first about Maths, the second about Spanish literature (we had to read a recently published novel by Gabriel García Márquez I remember, “El General en su Laberinto”), and a third one about “Cultura General”, a pot-pourri of questions about history, geography, politics, and the arts. We used to meet with a couple of friends at home during that year, preparing questions drawn from previous years’ exams.
Of course the Math exam was the one that everyone feared the most, including me. Yes, I’ve already told the story about how I taught myself calculus in a previous article, but still, there were many subjects in the exam that weren’t part of the standard curriculum, and we had to learn from scratch.
One of those subjects was trigonometry, and thankfully my school offered support to exam candidates like us, to have extracurricular classes during the afternoons (we had standard classes only during mornings those days). These extra classes were taught by a venerable and legendary professor whose family name has vanished from my RAM.
And among the myriad things he taught us during those preparation sessions, we had the eponymous acronym “SOHCAHTOA” engraved in our memory. For those who do not know, it’s a mnemonic rule to remember how to calculate the sinus, cosine, and tangent of an angle, as seen in a rectangular triangle:
- Sine: length of the Opposite side, divided by the length of the Hypotenuse.
- Cosine: length of the Adjacent side, divided by the length of the Hypotenuse.
- Tangent: length of the Opposite side, divided by the length of the Adjacent.
What am I even talking about you say? Well, maybe the image below will help (or refresh your memory):
And look at that: 37 years later… I still remember the rule and its meaning.