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Dave Richeson Profile
Dave Richeson

@divbyzero

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Mathematician. Curley Chair in Liberal Arts at Dickinson College. Author of Tales of Impossibility and Euler's Gem. Now: https://t.co/cefdX8CG6u

Carlisle, PA
Joined August 2008
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@divbyzero
Dave Richeson
8 months
I don't know my plan for Twitter/X. It is hard to give up after all the great people I've met and conversations I had in 13+ years, but the math community has moved to Bluesky. I will use as my go-to site for posting math content now. Join us there!.
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@divbyzero
Dave Richeson
8 months
By the way, I just downloaded all my tweets so I'd have them for the future. It is a huge file, but the interface is pretty convenient. I was worried that X might have discontinued that option. Although all the branding is Twitter, everything downloaded without problems.
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@divbyzero
Dave Richeson
8 months
In case you are moving to Bluebky, you can find me here:
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@divbyzero
Dave Richeson
8 months
These are all screenshots of my Excel spreadsheet! You can download the spreadsheet from my blog.
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@divbyzero
Dave Richeson
8 months
New blog post! I used ChatGPT to help me create a Mandelbrot set in Excel! Here are the 30x30, 60x60, and 250x250 versions. I'm also including a few zoomed-in views.
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@divbyzero
Dave Richeson
8 months
I guess, now that I've posted this, I realize this isn't *quite* right. If A is 0, then after Z would be BA. If A was 1, then after Z would be A[0].
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@divbyzero
Dave Richeson
8 months
Some different bases for numbers and who used them. Base 10: Egyptians.Base 60: Babylonians.Base 20: Mayans.Base 2: Computers.Base 16: Computers.Base 26: Microsoft Excel
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@divbyzero
Dave Richeson
8 months
Here's a fun little "magic trick." Can you figure out how it works? Hint: even and odd numbers. I was thinking you could roll a die to determine how much to count each time. (I saw the trick was credited to Martin Gardner—true? Source?)
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@divbyzero
Dave Richeson
8 months
typed in my request and pasted a screenshot of the equation from the article. Within five minutes, it was plotted! I then took a true cardioid, scaled and translated it so it was atop the other heart-shaped curve. As you can see, they are nearly indistinguishable!.4/4
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@divbyzero
Dave Richeson
8 months
smaller heart-shape is the image of the unit circle under a messy complex map (see below). I wanted to see it with my own eyes, but I didn't want to have to figure out how to graph this beast. So, I asked ChatGPT for the code to graph it in Sage. I .3/4
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@divbyzero
Dave Richeson
8 months
know about complex dynamics told me that although these smaller shapes look like cardioids, they aren't cardioids. They are slightly deformed. Not that I doubted them, but I wanted to see this written down somewhere. I found this article from 1995, which says that this .2/4.
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@divbyzero
Dave Richeson
8 months
Here's another neat generative AI example. It is well known, and not hard to show, that the main component of the Mandelbrot set is a cardioid. Looking around the Mandelbrot set, you'll see other cardioid-looking shapes. On the right, you can see the largest one. People who .1/4
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@divbyzero
Dave Richeson
8 months
AI."."Keep calm and wash your hands.". ChatGPT told me this is a "snowclone.". Indeed, there is a wikipedia page for the term
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@divbyzero
Dave Richeson
8 months
all alike; every unhappy family is unhappy in its own way." from Anna Karenina and rephrase it as "X Y are all alike; every un-X Y is un-X in its own way.". Some examples include:."Orange is the new black."."To snack or not to snack. That is the question."."AI is dead. Long live.
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@divbyzero
Dave Richeson
8 months
Another use of LLMs: I asked the following hard-to-google question. What is it called when you take a famous phrase and swap out the words so the sentence still has the same form but is applied to something different? For instance, one could take the sentence "Happy families are.
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@divbyzero
Dave Richeson
8 months
Here are my attempt to get Dall-E to make a "Mandelbrot[wurst]" or "[Mandel]bratwurst."
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@divbyzero
Dave Richeson
8 months
RT @hschhaya: (Inspired by @divbyzero). In an effort to get something other than politics into your feed, a fun fact about ‘49’. The sum of….
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@divbyzero
Dave Richeson
8 months
In an effort to get something other than politics into your feed:. A Munchausen number is the sum of its digits raised to the power of that digit. 1=1¹ and 3435=3³+4⁴+3³+5⁵ are the only two examples if 0⁰ is defined as 1. If we take 0⁰=0, then 438579088 is another.
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@divbyzero
Dave Richeson
8 months
Here's the @geogebra applet.
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@divbyzero
Dave Richeson
8 months
I decided to make a little video using @geogebra illustrating the relative sizes of the planets, the orbits of the planets, and an assortment of stars (including WOH G64, the largest star of known radius—1540 times the radius of our sun!).
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