I didn’t ace calculus when I was in university.

The two courses on mathematical analysis (Calc1 an Calc2) that I took earned me a “B” from the university’s math department. My late professor in Calc1 was an esteemed PhD who contributed significantly to the world of maths. My Calc2 professor was equally the same — though I can’t remember her name now (Dr. Guerrero, I think?).

I did struggle through calculus — my high school never taught us proper precalc. Sure, they taught us algebra and trigonometry and physics and formulas, but they just were simply not enough for college-level calculus.

Anyway, all that matters now is that I did get a B and I passed.

One thing that I did miss, however, is what one may call the “essence” of what calculus is all about. Sure, I was taught the concept and theory of limits, the epsilons and deltas, and the rules and techniques of derivation and integration. But I never really got it into my head “why” these were so.

Until I saw this video on YouTube.

This video (and the succeeding ones) clearly defined and summarized what the essence of calculus is for me — and fired up a renewed interest and appreciation of the subject that gave me nightmares in college.

I am sharing this just in case there are other people like me out there who had to go through calculus without really knowing “why” the formulas and techniques and theorems and identities and rules were so.