Simulation Updated +Created
E-learning websites must keep content free, only charge for certification Updated +Created
Charging for certification is fine. Creating exams and preventing cheating has a cost.
Another thing that is fine charging for is dedicated 1-to-1 tutor time. This is something Udacity is doing as of 2022.
www.investopedia.com/articles/investing/042815/how-coursera-works-makes-money.asp has a good mention:
MOOCs were first created by people with utopian visions for the internet. This means the idea for platforms like Coursera was likely conceived without a business plan in mind. Nonetheless, Coursera has managed to monetize its platform. It is worth noting, however, that monetization has lead to the effective elimination of the original MOOC idea, which is predicated on ideals like free and open access, as well as the building of online communities.
Coursera users must pay to engage with the material in a meaningful way and take courses for individualistic purposes. This has been a consistent trend among all major online education platforms.
and it links to: www.freecodecamp.org/news/massive-open-online-courses-started-out-completely-free-but-where-are-they-now-1dd1020f59/, very good article!
That is a fundamental guiding principle of OurBigBook.com. The educational content must be licensed CC BY-SA!
Perhaps the most reliable way of reaching this state is E-learning websites must allow students to create learning content.
Bibliography:
Rational number Updated +Created
Real number Updated +Created
A good definition is by using Dedekind cuts.
Early Google employee Updated +Created
ChatGPT produces:
  • Heather Cairns (Employee #4) - Joined in 1998. She handled HR and was one of the earliest administrative hires.
  • Harry Cheung (Employee #5) - Joined in 1999. An early engineer.
  • Gerald Aigner (Employee #6) - Hired in 1999. Worked as a software engineer.
  • Susan Wojcicki (Employee #16) - Joined in 1999. She rented her garage to Larry and Sergey in 1998 and later became an integral part of Google's business and advertising teams.
  • Marissa Mayer (Employee #20) - Hired in 1999. Played a major role in Google Search and design.
Omid Kordestani - Joined in 1999 as Google’s first business hire, focusing on sales and revenue generation.
BitcoinStrings.com Updated +Created
bitcoinstrings.com has all strings -n20 strings, we can obtain the whole thing and clean it up a bit with:
wget -O all.html https://bitcoinstrings.com/all
cp all.html all-recode.html
recode html..ascii all-recode.html
awk '!seen[$0]++' all-recode.html > all-uniq.html
awk to skip the gazillion "mined by message" repeats.
A lot of in that website stuff appears to be cut up at the 20 mark. As shown in Force of Will, this is possibly because they didn't use -w in strings -n20, and the text after the newlines was less than 20 characters.
That website can be replicated by downloading the Bitcoin blockchain locally, then:
cd .bitcoin/blocks
for f in blk*.dat; do strings -n20 -w $f | awk '!seen[$0]++' > ${f%.dat}.txt; done
tail +n1 *.txt
Remove most of the binary crap:
head -n-1 *.txt | grep -e '[. ]' | grep -iv 'mined by' | less
Wave-particle duality Updated +Created
The history of light if funny.
First people thought it was a particle, as per corpuscular theory of light, notably Newton supported the corpuscular theory of light.
But then evidence of the diffraction of light start to become unbearably strong, culminating in the Arago spot.
And finally it was undertood from Maxwell's equations that light is a form of electromagnetic radiation, as its speed was perfectly predicted by the theory.
But then evidence of particle nature started to surface once again with the photoelectric effect. Physicists must have been driven mad by all these changes.
Cuisine by region Updated +Created
Ikigai Updated +Created
Software bibliography Updated +Created
Twitter Updated +Created
Sparse matrix Updated +Created
IBM 705 Updated +Created
SVG tutorial Updated +Created
SVG version Updated +Created
Chemical vapor deposition Updated +Created
Siemens spinoff Updated +Created
Einstein notation for partial derivatives Updated +Created
The Einstein summation convention works will with partial derivatives and it is widely used in particle physics.
In particular, the divergence and the Laplacian can be succintly expressed in this notation:
In order to expresse partial derivatives, we must use what Ciro Santilli calls the "partial index partial derivative notation", which refers to variales with indices such as , , , , and instead of the usual letters , and .

Unlisted articles are being shown, click here to show only listed articles.