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John Rock @johnrockmath.bsky.social · 15/03/2026

I'm using the textbook I wrote for my real analysis class this semester. (The PDF is free.) A student asked if it's basically "Real Analysis for Dummies", and yeah, I suppose it is. Lots of details are included, but the scope is not as broad as other texts.

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Tien Chih @tienchihmath.bsky.social · 01/03/2026

It's finally here! "Linear Optimization: A Geometric Inquiry Course" gives an inquiry based course in linear optimization supplemented by technology for intuition building. A great class for interests in either pure or applied math! Physical Copies now on sale: www.619wreath.com/store/p53/Li...

619wreath.com

Linear Optimization: A Geometric Inquiry Course

"Linear Optimization: A Geometric Inquiry Course" is an inquiry based learning text for an undergraduate course in linear optimization. Taking a geometric vantage point to build intuition, students wo...

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Howie Hua @howiehua.bsky.social · 01/03/2026

Let's learn about lattice multiplication and why it works

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John Rock @johnrockmath.bsky.social · 14/02/2026

Here's a Desmos for checking to see if your threshold N actually satisfies its role in the definition for a converging sequence in the plane. The default N doesn't work! Can you fix it? www.desmos.com/calculator/z...

desmos.com

Threshold tester - 2D or complex

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John Rock @johnrockmath.bsky.social · 13/02/2026

I've been learning how to build Desmos activities for real analysis. This one helps build some intuition about the definition of continuity, and in turn it really helps motivate the search for a good threshold delta. www.desmos.com/calculator/e...

desmos.com

Continuity

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John Rock @johnrockmath.bsky.social · 30/01/2026

I made a mistake! A whole bunch of them, actually. Check them out in the errata for my textbook "Arbitrarily Close: An Introduction to Real Analysis": www.cpp.edu/faculty/jaro.... An updated PDF of the textbook with slightly fewer mistakes free to download.

cpp.edu

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John Rock @johnrockmath.bsky.social · 25/10/2025

Arbitrarily Close: An Introduction to Real Analysis has been published by 619 Wreath! Free PDF, Desmos, and GeoGebra available on my faculty webpage (at least for the time being): www.cpp.edu/faculty/jaro... Hardcover and paperback copies are available from 619 Wreath: www.619wreath.com/acl.html

Cover of the textbook Arbitrarily Close: An Introduction to Real Analysis.

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yt @anonbatard.bsky.social · 16/07/2025

I want to be romantic about baseball, but it broke my heart tonight instead

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Aaron van Dorn @aaronvandorn.bsky.social · 22/06/2025

Hey remember when the one of the most prominent Democrats in Minnesota and her husband were assassinated

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Howie Hua @howiehua.bsky.social · 28/05/2025

If you do the alternating sum of the digits of a whole number, you can tell if that number is divisible by 11. Here's how and why it works:

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Reposted by John Rock

Acyn @acyn.bsky.social · 24/04/2025

Walz: If you say you love freedom but you don't believe freedom is for everybody, then the thing you love is not freedom, it is privilege.

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George Takei @georgetakei.bsky.social · 15/04/2025

I see it. I have lived it. 83 years ago, the U.S. government turned upon a group of its own citizens and residents and sent them to internment camps without due process. I was there among them. American fascism is back. It is here. It is now.

A tweet by Sarah Longwell (@SarahLongwell25
) reads: "He’s threatening media companies who are critical of him. He’s talking about sending Americans to foreign prisons. He’s signing executive orders to investigate former staff members who spoke out against him. Don’t you see what’s happening here?"

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