Here's a nice "proof without words": The sum of the squares of several positive values can never be bigger than the square of their sum. This picture helps make sense of how ℓ₁ and ℓ₂ norms regularize and sparsify solutions (resp.). [1/n]

I only realize now that it was an april fools' post... I'm relieved and disappointed at the same time.

Nice and useful. Worth taking note of.

A regular hexagon and a square. What fraction of the area of the square does the red kite represent ? #WFIS #GeometrySnacks

Semicircle and Rectangle. What is the red angle?

Two squares share a side. Two congruent isosceles triangles. Prove that the three red points are indeed collinear. #GeometrySnacks

100 mph going forward. 50 mph going back. Why average speed IS NOT 75 mph: youtube.com/shorts/UHBjfiB… #MTBoS #ITeachMath

Steven Strogatz continues his amazing math series in the NYT - a simply terrific blend of great writing, incredible graphics, and compelling mathematics. nytimes.com/interactive/20…

My "Math, Revealed" series is freely available to anyone -- no paywall! -- in the thread below

1000 candies on a table each considered a pile of size 1. A "move" consists of taking three piles of the same size, eating one of them and combining the other two to make a bigger pile. What is the largest number of moves you could possibly conduct?

Today's Puzzle: Every odd number is the difference of two squares. Which even numbers are the difference of two squares?

#Puzzle 📐Prove that the yellow right triangle, the pink rectangle and the cyan square all have the same area. #GeometrySnacks

5-stars were commonly used on the ceilings of tombs and other buildings in Ancient Egypt to depict the heavens. They are usually not connected to one another, but they are connected in this ceiling in the Ptolemaic Denderah Temple to form a sort of tessellation.

A nice proof without words of the Pythagorean Theorem by Abu' l'Hasan Thâbit ibn Qurra Marwân al'Harrani (826-901) with 6 congruent 📐. The total area 𝓐 can be seen in two ways : 1⃣ 𝓐=🟥+ 3 📐 2⃣ 𝓐=🟩+🟦+3📐 So 🟥=🟩+🟦 Alexander Bogomolny proof #24 cut-the-knot.org/pythagoras/

Like an hour ago, my kids decided they were mathematicians and began a series of investigations (on their own). 1+2+⋯+10=55 11+12+⋯+20=155 21+22+⋯+30=255 etc. They conjectured the general theorem. Pretty exciting.

#SundayPuzzle. A red right-angled triangle and its incircle. Prove that the blue rectangle has the same area than the red triangle. #GeometrySnacks

#GoldenRatio rectangle construction with GeoGebra #Fibonacci #spiral 🌀 #mathgif

Only for geniuses. 🤣 Use @edsouthall