[Sesse__]

It's a US thing. Europeans just write 1/cos(x) instead of treating it as a special thing with its own name. The Americans have sec, csc, and a bunch of others I never bothered to learn. It doesn't seem to add all that much to me? (Of course, it's a bit hypocritical since I gladly use tan(x).)

[RichardLake]

I imagine it was more useful when using tables to lookup/approximate the values before calculators with trig support were a thing.

[GeoAtreides]

speak for your own european country, in my neck of the woods (EE) we were taught and we worked with both secant and cosecant.

[oersted]

They were taught to us in Spain, I suppose they don't make an appearance often, but they are perfectly familiar.

[thelaxiankey2]

the only other one is cot, actually.

Personally I thought they were nice to have because coming up with the integral of 1/cos on the fly is pretty brutal in a long integral

[fsckboy]

there are these old-fashioned looking drawings...

(quick search, didn't find the old ones, but similar to these)

https://mathematicaldaily.weebly.com/secant-cosecant-cotange...

https://www.pinterest.com/pin/enter-image-description-here--...

... which were not used in my education but whenever i saw them i wished they had been, they lay out a geometric interpretation of all of them. by "old" i mean "look like Leonardo drew them"

[sebzim4500]

In the UK we certainly use sec(x)

[jebarker]

I used sec, cosec and others during my math degree in the UK too.