Comments for David Richeson: Division by Zero
https://divisbyzero.com
Wed, 04 Apr 2018 19:47:37 +0000hourly1http://wordpress.com/Comment on I Heart Cardioids by calcpad
https://divisbyzero.com/2018/04/02/i-heart-cardioids/#comment-58837
Wed, 04 Apr 2018 19:47:37 +0000http://divisbyzero.com/?p=5171#comment-58837I didn’t know about the coffee cup. This one was very interesting to me. Thank you!
]]>Comment on I Heart Cardioids by Dave Richeson
https://divisbyzero.com/2018/04/02/i-heart-cardioids/#comment-58836
Wed, 04 Apr 2018 16:00:03 +0000http://divisbyzero.com/?p=5171#comment-58836Thanks for the comment and the link! I updated my post with this info.
]]>Comment on I Heart Cardioids by Rick Wicklin
https://divisbyzero.com/2018/04/02/i-heart-cardioids/#comment-58835
Wed, 04 Apr 2018 13:22:36 +0000http://divisbyzero.com/?p=5171#comment-58835Wonderful description of the elementary properties of caustics in a coffee cup. You might be interested (or already know) that if you assume the light rays are coming from infinity (thus are parallel) then the caustic is called a “nephroid,” which is a cousin of the cardiod. More than 20 years ago (1996), Vic Reiner and I wrote a computer lab for a senior-level course in algebraic geometry at U Minnesota. The lab, called the “Nephroid Lab”, is still available on the internet: http://www.geom.uiuc.edu/~fjw/calc-init/nephroid/ Check it out!
]]>Comment on I Heart Cardioids by shivaniuniverse
https://divisbyzero.com/2018/04/02/i-heart-cardioids/#comment-58833
Tue, 03 Apr 2018 03:37:45 +0000http://divisbyzero.com/?p=5171#comment-58833Beautiful post!
]]>Comment on Finite differences of polynomials by Gene Chase
https://divisbyzero.com/2018/02/13/finite-differences-of-polynomials/#comment-58737
Wed, 14 Feb 2018 03:24:56 +0000http://divisbyzero.com/?p=5164#comment-58737When I first came to Messiah College in 1973, all Computer Science majors had to take Numerical Analysis. At the time I focused on Newton: Newton’s forward difference formula, Newton’s backward difference formula, Newton’s central difference formula. Later when I wanted to work more history into the curriculum, I had students learn about Babbage’s Difference Engine. Sadly, the course Numerical Analysis has fallen by the wayside. I regret most the chapter on propagation of errors falling by the wayside. Finite differences can help to detect the propagation of one kind of error. A ghost of that chapter shows up in machine architecture when discussing single- versus double-precision floating point numbers. Otherwise, nothing, sadly.
]]>Comment on Finite differences of polynomials by Oscar Cunningham
https://divisbyzero.com/2018/02/13/finite-differences-of-polynomials/#comment-58736
Tue, 13 Feb 2018 18:05:26 +0000http://divisbyzero.com/?p=5164#comment-58736This gives a convenient way to extrapolate a sequence. Just calculate the differences until you get a constant (possibly because you’ve reduced the number of terms to 1) and then work your way back up assuming that that row continues to be constant. If your terms actually do come from a polynomial then this method can continue the sequence despite never actually calculating the coefficients of the polynomial.
]]>Comment on Math Crafts: Salt Designs, Newton Snowflakes, Fractal Christmas Trees, Paper Pentagons, and Flip Books by mathematicsstudent
https://divisbyzero.com/2017/12/18/math-crafts-salt-designs-newton-snowflakes-fractal-christmas-trees-paper-pentagons-and-flip-books/#comment-58716
Tue, 23 Jan 2018 22:23:53 +0000http://divisbyzero.com/?p=5143#comment-58716This is so cool!
]]>Comment on Card Table Proof of the Pythagorean Theorem by Pythagorean Theorem Lesson – Rethinking Math Class
https://divisbyzero.com/2017/05/30/card-table-proof-of-the-pythagorean-theorem/#comment-58583
Thu, 27 Jul 2017 11:50:11 +0000http://divisbyzero.com/?p=4975#comment-58583[…] neat when people see math outside of the classroom and take a picture of it. I read a post from Dave Richeson that showed a neat way to demonstrate the pythagorean theorem, however, I often wonder how might I […]
]]>Comment on Card Table Proof of the Pythagorean Theorem by J. Franklin Richeson, M.D.
https://divisbyzero.com/2017/05/30/card-table-proof-of-the-pythagorean-theorem/#comment-58478
Wed, 31 May 2017 13:40:07 +0000http://divisbyzero.com/?p=4975#comment-58478Pretty neat!

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]]>Comment on Card Table Proof of the Pythagorean Theorem by Dave Richeson
https://divisbyzero.com/2017/05/30/card-table-proof-of-the-pythagorean-theorem/#comment-58477
Wed, 31 May 2017 12:54:21 +0000http://divisbyzero.com/?p=4975#comment-58477Thanks! I thought about the “found math” site when I took the picture.
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