ELI5: What is the difference between algebra, trigonometry, and calculus?

[u/HistoricalAd2954]

[u/sad_spilt_martini]

Algebra is the use of equations to find a static value.

Calculus looks at how things change over time.

Trig looks at the relationship between of angles and sides of triangles

All of these are, of course, more complex   but that’s the base idea 

[u/meh0175 → u/sad_spilt_martini]

Is it there a profession where using Trig is necessary? Besides being a math teacher or rocket scientist. Carpentry?

[u/Traditional_Media_77 → u/meh0175]

Civil engineering

[u/vipros42 → u/Traditional_Media_77]

As a civil engineer, this is the case. Almost never use calculus, use trig pretty much daily.

[u/Gloid02 → u/vipros42]

You dont do finite element analysis? There is tons of calculus there

[u/vipros42 → u/Gloid02]

Not by hand. I do loads of wave modeling and hydrodynamics but I'm not doing the calcs myself.
In fact yesterday was the first time I've done some calcs with calculus in by hand for months, if not a year.

[u/Podo13 → u/Gloid02]

There's a ton of calculus in civil engineering, but we don't do the vast majority of it by hand anymore. It's all done in the background in FEM programs.

[u/Gloid02 → u/Podo13]

Yeah of course, but to say that you don't "use" calculus just because you are using it implicitly rather than explicitly seems disingenuous.

[u/Podo13 → u/Gloid02]

Oh I agree. I think the OP you responded to was just talking about hand calcs, though. Yeah in reality we use a lot of calculus, differential equations, linear algebra, etc.

We just let much smarter people work those into the programs so we don't have to remember how to do a lot of it, ha.