Reddit mentions of Essential Mathematics for Computer Graphics Fast

It's hard to overstate the importance of maths & physics to the FX TD role, particularly in the more senior positions.

While it's true that no director will ever want physical accuracy - seriously, NO director EVER wants physically accurate - NEVER EVER say 'but that's what would happen!' - you still need to make the motion feel believable and a solid understanding of physics is very helpful in this regard.

I'm trying to remember the extent of the GCSE maths I did, but iirc you probably haven't started doing much calculus - understanding how force integrates to velocity and velocity integrates to position is fundamental to understanding the underpinnings of most particle & fluid solvers - you might have done a fair bit of this with A-Level physics though, I'm buggered if I remember what I did (I did both maths & physics at A-Level followed by an engineering degree).

As noted, linear algebra is what you'll be dealing with mostly at the geometry level, basic vector math, understanding vector addition, multiplication, dot/cross products and that kind of thing is extremely useful (I'm constantly shocked at the number of "FX TDs" who can't do even this), closely followed by space transforms using matrix math, in particular, how to transform/invert transforms (usually to unfuck some goddamned idiot animator's idea of motion) to get things in the right space to simulate, followed by the transform back to the right space to render. Quaternions are also incredibly useful, think of them as a shorthand for representing an object's orientation in 3d space - a position and a quaternion is mostly enough to represent where an object is in 3d space, you need to know that you can turn these two things into a 4x4 transform matrix as well as a 3x3 rotation matrix as well as how those matrices can be used creatively.

The good news is that most of this shit isn't that complicated, but it takes someone who really understands it (and how it relates to vfx) to be able to explain it in any kind of meaningful way.

As always, I'll throw out my usual book recommendation for this shit (if you can find it - buy it second hand on amazon, you want the one with the purple cover)
https://www.amazon.com/Essential-Mathematics-Computer-Graphics-Fast/dp/1852333804

Khan Academy and Scratchapixel are also very useful.

If you'd like a (e)book, Essential Mathematics for Computer Graphics is a great little reference guide on trig, vectors, matrices, and the like.