Phil Keller

I’m x^2 + 6x, you’re 9…

Silly SAT hack: say you have two points and you need the equation of the line. You know how to do it and you COULD do it but you feel lazy...maybe the #s are a little ugly...so you go to Desmos, put the coordinates in a table and then hit the regression button... #Iteachmath

Glad to hear that I am once again out ahead of the curve. I was also an early adopter on grade deflation. Not as a teacher, but definitely as an undergrad.

Laws of physics still working. And I will never not be entertained by this one. (Sound on!) Note which washers leave the stick. They are placed at 10 cm intervals. #Iteachphysics

My plan to fix tanking in nfl, nba: a roll of die AFTER the season determines n, the number of end-of-season games that don’t count toward record for draft order. (NBA would roll 2 dice). Then, first tiebreaker: team with BETTER record in those n games. I bet Giants and Raiders might play to win…

Wait, we’re counting the download folder?!

For physics, there is no single piece of equipment I would find more valuable than a single copy of the Interactive Physics software.

How much time is lost to disputes over creative differences? I think in real life, the answer might be infinity. Or n + 7 where n is how long it takes for them to stop working together and you get two snowmen.

Here’s a list no one needs to see: top ten things my dogs are excited to find while out in a walk…

…yeah, let’s let this go.

I have a 1 kg tungsten cube. I tell my students that it is the official kilogram from Paris and that when they adopted the new official kilogram, this one was no longer needed. They put it on EBay and I was able to snag it. (It would seem that telling such nonsense is a perk of the job. )

On the old place, PEMDAS was the first word I blocked. And yes, if there is a way to say ambiguous things, the answer is not to argue (endlessly) about those statements when we could choose to make clear statements instead. This is also true in mathematics.

iykyk...

Yeah, this is appalling so many ways. But I hadn’t even considered the (likely?) possibility that my letters are now being used to train their AI. Can they do that without my consent , I wonder (as if I’ve been living under a rock)?

This is an amazing update to what was already superb!!! (And I will be studying it to try to learn how you did it! I tried and failed to add some of these enhancements on my own)

I wondered for a moment what work you were sending to the space station…Mr Aura indeed

I can’t disagree: we did this problem today!

Also, can I add that it is easy to write projectile problems that are way too hard, with challenging math but maybe not much more in physics understanding to be had.

I hope I don't "enforce" it either :) These are all style preferences, perhaps more useful for beginner problems. Still, I'd be curious to see an example of the kind of problem you are thinking of where the method is too constraining.

But I think I may see where you are coming from. Are you of the no-substitutions-until-all-algebra-is-finished school? If so, you are probably in the majority. I admit I am lax about that. So my students get away with solving for t and then substituting. That may be how we evade this issue

Well, okay. But the point is not to make doctrine but to encourage disciplined examination of each item. So given a launch speed of say 20 m/s at 30 degrees, I can ask: is that horizontal? No. Vertical? Still no. But it has components…

I make a chart that keeps horizontal and vertical separate but make a big deal that when either side of the chart hands you enough info to solve for time, you can “send that to the other side”. Is that what you are asking about?

We are not afraid!

Silly question: how are you measuring time? We started getting decent results when we switched to using phones. Now most groups are seeing errors of 5% or better. I can tell them that 30% is a measurement issue but say, 240% is a calculation error. Which mass spins? Which one hangs? 🤷‍♂️

“That’s seasonal” is apparently trader Joe fancy talk for “yeah we don’t have that”. Like calling it seasonal, giving false hope of eventual return will make things better. I see right through that…

If you are new to using Desmos, I have some brief intro videos here:

www.youtube.com/@digitalsatg...

Silly to take the SAT without these skills…

In case any of you work with SAT students, here’s a quick heads up: starting with the August test, the calculators that “do algebra” are no longer permitted. (So desmos fluency is even more important!). #Iteachmath

Agreed! But many textbook proofs use the binomial thm approach which has the same flaw. Btw, logarithmic differentiation gets it all in one swoop but it comes later in the curriculum. Good thing pedagogy can stray from the sequencing demanded by the proofs :)

Not saying it’s the best way, but I just realized you can show that the derivative of x^p =px^(p-1) for all positive integers p using the product rule and then induction. Just saying…#iteachmath

If the agreed convention is that .5 and greater rounds up, and if if we are interpreting “0.4999…” as a shorthand for the associated infinite sum, I think you have to round up. But it’s a fun question. It’s like, do you believe the math or not?

Things we need, things we don’t