You're not alone. I did the same in my mid-40's.

A great book for brushing up/re-learning pre-calc is "Precalculus Mathematics in a Nutshell"[0] by George F. Simmons (you can find it used cheap). He really boils it down to the essentials. For example here's how he opens his chapter on Trig:

"Most trigonometry textbooks have been written by people who appear to believe that the importance of the subject lies in its applications to surveying and navigation. Even though very few people become surveyors or navigators, the students who study these books are expected to undertake many lengthy calculations about the heights of flagpoles, the widths of rivers and the positions of ships at sea. The truth is that the primary importance of trigonometry lies in a completely different direction - in the mathematical description of vibrations, rotations, and periodic phenomena of all kinds, including light, sound, alternating currents and the orbits of the planets around the sun. What matters most in the subject is not making computations about triangles, but grasping the trigonometric functions as indispensable tools in science, engineering and higher mathematics. These functions and their properties are the sole subject matter of this chapter."

The entire book has that vibe. It's wonderful.

[0]https://www.amazon.com/Precalculus-Mathematics-Nutshell-Geom...

I went to college late, after a few years out in the world. I had not originally intended to go into a technical field, but realized that's where some of my passions were so I went after a CS degree. Not coming from a technical place I had put almost no effort into mathematics during public school and so I found myself very very behind.

I bit the bullet and focused my first few semesters almost entirely on remedial math education, trying to fill in that gap. Because I now had a strong motivation, a little age, and focus, I managed to become a very good math student and even received the occasional award during my undergrad math education.

I've lost much of it, but I now know I can learn it, and many of the topics that had intimidated me at first turned out to be not a big deal once I got it. One day as a hobby I plan on starting over from algebra and work up again for fun.

I do this all the time. There's nothing at all weird or embarrassing about it. 10 years ago I was sure I'd remember and have an intuition for the trig identities, but I'm still looking them up every time now.

Also, even in pretty advanced CS (at least in my field, security and, particularly, cryptography), most of the nuts-and-bolts math is high school math.

Nothing to be embarrassed about. This stuff is very "use it or lose it" so unless you're really using it regularly, it fades from mind very easily. Heck, I've taken College Algebra like 3 times over the years, and I still keep going back to Khan Academy or watching various Youtube videos and the like, for a refresher here and there. And that's just to keep the basic algebra stuff in mind.

I have a master's degree in CS, and I feel the need to do this too. Use it or lose it. Problem is you only use bits and pieces of what you learned here and there, not enough to remember college level math.

My hat is off to you. I did the same thing, mastering something like 85% of the material in the Mathematics area of Khan Academy before finally just enrolling at a university part-time to go deeper. Now that you're older you'll be better able to pause at moments and reflect on the deeper meaning of some of the thing you're learning. Enjoy!!!

I've been doing this as a "wait for queries to run" kind of brain game. I don't think it's embarrassing. I don't think we emphasize "back to basics" in enough areas of life, except when we hit a wall after failing to achieve what we meant to and more often than not B2B solves the problem.

I don't think anyone can ever fault you for taking the initiative and learning it in your own time.

I feel the same way though, I've been looking back through some basic algebra on Khan Academy too because I feel maths is very much my weak point.

My mom always told me I'd need better Math grades to become a programmer.

Since the 2nd program I ever wrote was a script to do my math homework for me, I laughed at her.

Then I failed to pass the first year of CS bachelor. Twice.

I am very glad to see this most excellent book here, and will add it to my collection.

How did that happen? The required math courses got in the way?

Also attempting to finish CS BS but I have hit a wall in my late 30s unable to pass pre-calc. I shudder at the daunting levels of Calc that come after to the point that I'm debating switching majors just to "get a degree".

This may not work for you, but I honestly didn't understand calculus until I worked through Knuth's Concrete Mathematics. There's a portion of it detailing rules on summations, which were (I realized at the time) the discrete equivalent of integration (summation of functions over integers versus integration which is summation of continuous functions). With my (stronger) CS than math background, it just "clicked" for me. You could check out the book from your university's library and see if this material helps you. I can't put my finger on which specifically now (too many years later) but various calculus concepts just fell into place as I worked through those portions of the book.

I'm doing something similar. As an undergraduate I studied biological sciences in the U.K. and in the U.K. they don't think biologists need to know any college-level Math(s). Or at least they didn't when I did it. Just a stupid Maths for Biologists class with one of those ridiculous "learn Statistical Tests as recipes" syllabuses. (This was at Cambridge) I really regret not taking the first year intro to applied math courses that those studying chemistry and physics took.

I dropped out of college and never went higher than pre-calculus, and I went back to learn all of this stuff with Khan Academy in my 30s, as well. It's an amazing resource.

I'm almost 34 and when I watch Calculus One videos on coursera, I sometimes get stuck when the guy easily expands (a + b)² or folds it back. We used to to this at math class at school and then probably in university, but I haven't been doing anything like this since then (talking about importance of math for programmers!).

Very much this. My son is taking his first course in HS Algebra. Fortunately, he generally gets it, but every now and then asks me for help in understanding a concept since his textbook is awful. I've found myself having to Google topics that I know I mastered decades ago. It does come back, but sometimes it takes a bit of thinking.

I recently started a similar journey, starting with basic pre-algebra, let's just say its been a humbling experience.

I did something similar. I returned to college in my late-20s to get my degree, and started at trig and worked my way back up. It wasn't strictly necessary, but I'm glad I did it.

Good luck with your studies, and never feel embarrassed to better yourself!

We are in the same boat. I wish I've had taken my math classes more seriously.