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It looks like a very nice careful description, but where is the physical intuition? Where's the plots of tangent lines on a function at various points?

There's nothing wrong with the article (I think), I am just curious about the pedagogy and motivation for not immediately introducing a graphical conceptualization of a derivative especially for such a "from the ground up" exposition.



Hi, author here. This is what made derivatives finally click for me (as opposed to the tangent line) so that’s how I wanted to explain it...maybe the same thing would click for others!


I was looking for a tutorial on derivatives the other day and most of the results popping up at the top of Google were a bit dry.

This one is very good though. Excellent work.

How did you do the diagrams?


The Procreate app on the ipad


Do you have any recommendations for learning the app to make what you’ve made?

I don’t suppose I could bribe you into recording a video of yourself making some diagrams...

Your algorithms book is excellent and fun!


IMO it is more about drawing ability vs app knowledge, so I would suggest learning to draw! Just start drawing and you'll get better over time. You could join something like https://streak.club/s/8/daily-art to keep motivated.


The daily art streak was an awesome suggestion, thank you.

I have one specific question. When you write in your diagrams, what brush settings do you use? Are you using calligraphy mode?

The handwriting in your diagrams has a unique look and feel that I was hoping to emulate.

For example: https://i.imgur.com/8Bb1wEY.png

That question mark is beautiful, and the thickness varies in a particular way that is quite unlike regular handwriting. It's more like chalk on a chalkboard. That's why I was hoping to know the exact settings.

I spent some time with the Procreate app today and was able to pick up the basics. I'll try learning by copying your work. Thanks again!


Oh I see ... that's done non-digitally using a fountain pen.


For what it's worth, I like this much better. I had the traditional method of graphs and tangents. I was slightly lost on it in Cal I, and I could regurgitate it in Cal II. "The derivative of a function is the amount of change of the output with respect to the input." This is another level of derivatives clicking


And thank you for it. Tangent lines have never meant much to me; your way of explaining feels much more intuitive.

Also, I love your algorithms book! It is the main resource I used when preparing for my coding interviews.

Thanks again, I look forward to your next project!


Thank you!


Hi author. There is a typo in the section How To Calculate The Derivative. The first two images in that section label 0.1^2 as "input change" in the denominator. It should be 0.1, not squared.


Echoing the sibling comment: How'd you make the diagrams? They're quite lovely and I'd like to follow your process.


I do not really learn a concept until I can visualize it somehow. Indeed, when I was learning derivatives, it did not click until I saw a graph with a tangent line. But everybody is not the same way. Some people prefer to develop their intuition based on a text explanation, some people need an example with numbers, some other people need an actual person to explain it to them in spoken words.

When you learn better with one of these methods, seeing another one first may confuse you instead of helping. Moreover, once you have understand the concept, other kinds of explanations tend to broaden your view of the topic.

I think this a great non-visual explanation of derivatives. No more, but no less. I think it has a great pedagogical value, even if it is not the best introduction for my way of learning.


Way back when I was in high school what made derivatives click for me was the notion of "Rate of Change" applied to time series.

I think it is called Parametric Calculus.

v = u +at; v^2 = u^2 +2as;

and all that

Velocity = ds/dt and acceleration = dv/dt = d^2S/dt^2

At least in my mind rate of changes makes a lot of sense to explain derivatives.

edit: i.e Acceleration is the rate of change of velocity over time.


Reducing explanation of the derivative at an intuitive level to 'simply the rate of change' confuses the hell out of people when they encounter other things that are also defined as derivatives but do not describe a change in any obvious sense. For example, electric current (or, say, a flow of water) through a cross-section of a closed circuit does not necessarily represent a change of electic charge (or the mass of water) on either side of the surface, as it remains constant.




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