you can also ‘trivially’ derive the quadratic formula using completing the square, but does anybody actually do that instead of just memorizing the formula?
That depends on how often you use it. If I needed to write quicksort as often as the quadratic formula, I’d probably remember it. And if I only used the quadratic formula as often as I do quicksort, I’d just derive it each time.
Honestly, for the first year or two after learning about it (which is the only time where it’s really relevant) that’s exactly what I did. Spend 30 seconds, derive something that’s definitely correct, and never worry again about your memory randomly failing you
you can also ‘trivially’ derive the quadratic formula using completing the square, but does anybody actually do that instead of just memorizing the formula?
That depends on how often you use it. If I needed to write quicksort as often as the quadratic formula, I’d probably remember it. And if I only used the quadratic formula as often as I do quicksort, I’d just derive it each time.
Honestly, for the first year or two after learning about it (which is the only time where it’s really relevant) that’s exactly what I did. Spend 30 seconds, derive something that’s definitely correct, and never worry again about your memory randomly failing you