The 1959 union film on pipefitters learning to build nuclear reactors led to an irrelevant sidebar.
The narrator is emphasizing the complexity of the physics and math needed for reactors. The plumbers had to learn a new vocabulary, a whole new way of thinking. “Specific heat, latent heat, sine, cosine, tangent, cotangent, secant and cosecant.”
Whoa there! I vaguely remember learning the last three in school, but those are NEVER USED in real graphics or programming now. Programming languages and graphics systems use sine, cosine, tangent, inverse tangent. That’s all. I use sin and cos constantly in programming, graphics and thinking. Sin and cos are a more active part of my life than adding and subtracting.
Well, is this new? Did this restriction start with programming? No, the typical slide rule has sin, cos, tan. You don’t need the inverses on a slide rule. Instead of setting the angle and reading the tan, you set the tan and read the angle. I’ve never seen cot, sec, csc on a slide rule or a computer language.
Slide rules haven’t changed much since the 1880s at least. This 1875 book describes how to use a slide rule with sin and cos only.
Looking up the other three just for fun, cotangent is the reciprocal of tan, secant is the reciprocal of cos, cosecant is the reciprocal of sin. You don’t need them at all, even for paper calculations or slide rule calculations.
So why in the hell did we learn them in school? At the time we learned them, nobody ever used them!
Most of what we “learned” in school was destructively wrong. The rest was pointless.
Polistra's Mill 