WHY IT WORKS
One topic. Two explanations.
Professor in the lecture hall
“The derivative of f(x) at x₀ is the limit of the ratio of the function increment to the argument increment as the latter tends to zero.” You wrote it down. Understood nothing. Too shy to ask — 200 people in the room.
Your tutor’s clone
“Look: you’re driving and glance at the speedometer — it says 80 km/h. That’s the derivative. Not how far you’ve gone, but how fast you’re going right now.” Understood in 30 seconds.
The clone explains in the style that works for you — not by the textbook.