Dear Dr. Enenstein,

We may have called you *Mr.* at your insistence, but I know to give reverence where reverence is due.

And reverence, perhaps, has no worthier a recipient than a life-changer, particularly when that life can count on but one hand the others (outside family, of course) who hold the same lofty position.

*Dr. Enenstein*, *Life-Changer Enenstein*, but never just a *mister*, and certainly never just a *calculus teacher*.

In a lot of ways, I was a straight-A fraud. I may know what a tangent line is, and I may know what slope is, and I may be able to find a derivative. I may even have it emblazoned on my brain that a derivative is the slope of the tangent.

But I have a secret, one that I've held since high school: I've really no idea what a derivative is, you lost me somewhere on the z axis, and when I speak of integrals now, I speak purely in the non-mathematical sense.

And yet, here's what you taught me, lessons that were a shall-we-say *integral* part of my growing into an uncertain future:

## 1. Defiance.

When Carlmont would make no allowance in its attendance policy for my health, you sided with the administration and told me that if I missed a test, I'd get a failing grade just like the other class-cutters.

You'd never know it, and many will never understand it, but being treated like everyone else was exactly what I needed.

And so, when I had to have surgery the morning of a calculus test, I exercised my new-found defiance — not toward you, but toward hospital staff that greeted me when I awoke in the recovery room. I insisted — rather, demanded — that they allow me to leave and go to my calculus test.

And when I showed up, three minutes late with tardy slip in hand and surgical bandages on skin, you smirked and said, “Why are you here?” I just glared and demanded my test, secretly pleased.

## 2. Confidence.

When I felt good at nothing, you urged me to join the lunchtime calculus club.

This invitation-only group, to be honest, wasn’t actually my cup of tea. This should have tipped me off to the fact that later endeavors into multivariable calculus, linear algebra/discrete math, and non-Euclidean geometry wouldn’t be nearly as successful as my high school calculus experience. (You mean people actually talk about mathematical theory for fun and enjoy proving as-of-yet unproven postulates?)

But because of your vote of confidence, I felt like I had a new purpose beyond merely getting through the school day so I could get to the hospital for dialysis.

## 3. Philosophy.

Your strange end-of-year assignment to write an essay on our philosophy of life was the first time I sat down and grappled with my own metacognition. (Is that sentence recursive? My brain hurts thinking about it.)

I won’t rehash that philosophy here, but suffice to say, I let my defiance take shape once more with statements like “in my philosophy, I compartmentalize, so writing a philosophy paper in math class is weird” and “life doesn’t give lemons — you have only your perspective to thank for that bombshell.”

## 4. Problem-solving.

I remember a lot of things about calculus class. You had a tremendous impact on me. You were smart in math and in life. You were a voracious whiteboard-writer. And you crossed your T’s before you drew the vertical line.

These last two facts are important because, well, together they meant that I observed unconventional T-crossing nearly nonstop for an hour each day for an entire school year. I can still picture it so clearly. So engrained did your left-handed writing become that for the next two years, I too crossed my T’s before grounding the horizontal dash with the vertical line.

And guess what? The end result was the same. With mathematical proofs, you taught me that there were elegant solutions for getting from A to B and sloppy ones that involved unnecessary detours or overly complicated steps.. With some problems, though, you could take the same number of steps — but do things in a different order — and reach your end goal.

## 5. Ownership.

By unapologetically posting our scores on the classroom wall the day after a test, you showed that we all have to own our mistakes, sometimes painfully, and sometimes publicly.

So with your impact well-established, I’ll end this with *Quod Erat Demonstrandum*.

Or, should I conclude the way you taught us to wrap up proofs instead, because like a pHD in a high school classroom, Latin can seem a bit stuffy:

WWWWW. (Which Was What We Wanted.)

With fondness and gratitude,

Jessica