motd - 08/##/2024
-----------------
08/31/2024 Viviani's theorem:
https://www.futilitycloset.com/2024/08/27/peak-to-peak/
https://en.wikipedia.org/wiki/Viviani's_theorem
1. In equilateral triangle ABC, with height h and side
length a, pick a point P within ABC
2. Draw perpendicular lines from P to each of the three
sides AB, AC, and AB of triangle ABC. Let the lengths
of these lines be s, t, and u, respectively.
3. Draw lines from P to each of A, B, and C, to form three
triangles PAB, PAC, and PBC within triangle ABC.
4. Area ABC = (1/2)(a*h) = Area PAB + Area PAC + Area PBC
5. Area PAB = (1/2)(s*a)
Area PAC = (1/2)(t*a)
Area PBC = (1/2)(u*a)
6. Therefore, (1/2)(a*h) = (1/2)(s*a) + (1/2)(t*a) + (1/2)(u*a)
7. Diving by the common factor (a/2) leaves:
h = s + t + u
Thus, the sum of the shortest distances from any interior
point in a equilateral triangle to its sides equals the
triangle's height.
08/30/2024 The harmonic series converges in base 11 or higher:
https://www.johndcook.com/blog/2024/08/29/strange-harmonic-series/
Simple python test program:
https://srirangav.github.io/motd/2024/08/harmonic.py
08/26/2024 Don't use complex expressions in if conditions:
https://maximullaris.com/if_condition.html
08/26/2024 Macs compatible with MacOS Sequoia:
https://osxdaily.com/2024/08/26/macos-sequoia-compatible-macs/
08/26/2024 LUX-ZEPLIN rules out WIMPs above 9 GeV/c^2:
https://phys.org/news/2024-08-dark.html
08/26/2024 A book about the Iliad foils a robbery:
https://www.bbc.com/news/articles/cvg4kpv3p4zo
https://lithub.com/an-italian-robbery-was-averted-thanks-to-a-good-book/
08/24/2024 Making coffee at home as an economic signal:
https://rubenerd.com/making-coffee-at-home-as-an-economic-signal/
08/24/2024 OpenBSD of Theseus:
https://www.undeadly.org/cgi?action=article;sid=20240824114631
"With this commit, we have completed an amusing mission of
replacing the final parts of the original OpenBSD. We have
reached OpenBSD of Theseus."
08/22/2024 Oldest company in the world - Kongo Gumi:
https://www.openculture.com/2024/08/how-the-oldest-company-in-the-world-has-survived-nearly-1500-years.html
08/22/2024 The original 386 Sid Meier used to create Civ:
https://www.extremetech.com/computing/civilization-developer-shows-off-the-10000-386-pc-used-to-make-the-original
08/22/2024 Marathon, Marathon 2, and Marathon Infinity are free on Steam:
https://appleinsider.com/articles/24/08/22/classic-marathon-infinity-lands-on-steam-as-a-free-mac-title
08/22/2024 Civ VII is coming in Feb 2025:
https://appleinsider.com/articles/24/08/20/civilization-vii-is-coming-to-mac-in-early-2025
https://arstechnica.com/gaming/2024/08/civilization-vii-preview-a-new-age-dawns-for-this-decades-old-4x-series/
08/21/2024 APFS versions:
https://eclecticlight.co/2024/08/22/dual-booting-your-mac-with-multiple-versions-of-apfs/
08/21/2024 Antihyperhydrogen-4:
https://www.sciencealert.com/record-breaking-antimatter-discovery-could-help-us-find-dark-matter
The STAR experiment conducted at Brookhaven National Lab's
Relativistic Heavy Ion Collider recently detected "a
hypernucleus made of antimatter, or an antihypernucleus. ...
[I]t was the heaviest and most exotic antimatter nucleus
ever seen ... [and] consist[ed] of one antiproton, two
antineutrons and an antihyperon, and has the name of
antihyperhydrogen-4."
08/21/2024 The color of night:
https://www.atlasobscura.com/articles/what-color-is-night
"On Earth, even in the absence of light pollution or a Moon,
the sky is never totally black. Instead, a rainbow of subtle
colors appear[.] ... Bands of green and red appear through
the dark, a phenomenon called airglow. Rather than the light
of the Sun or Moon, this is the light of chemistry: Solar
radiation energizes atoms and molecules of air, which emit a
faint glow. So sometimes the night sky is reddish green, or
teal, or purple."
08/16/2024 Traceroute and modern firewalls:
https://utcc.utoronto.ca/~cks/space/blog/sysadmin/TracerouteFirewallRealization
"[The] default way that traceroute works is by sending UDP
packets to a series of high UDP ports with increasing IP
TTLs, and seeing where each reply comes from. If the TTL
runs out on the way, traceroute gets one reply; if the
packet reaches the host, traceroute gets another one
(assuming that nothing is listening on the particular UDP
port on the host, which usually it isn't).
...
Most firewalls are set to block unsolicited incoming UDP
traffic by default; you normally specifically configure them
to pass only some UDP traffic through to limited ports (such
as port 53 for DNS queries to your DNS servers).
...
The best way around this is probably to use ICMP for
traceroute ... Most Unix traceroute implementations support
'-I' to do this."
08/14/2024 AMS finds a surplus of deuterons:
https://www.sci.news/physics/deuteron-flux-13175.html
08/10/2024 Start by doing the math:
https://forestfolkcomic.tumblr.com/post/758426008050368512/forest-folk-410-081024
08/10/2024 Pros and cons of setting a root password on Debian:
https://www.reddit.com/r/debian/comments/1eoq6o3/should_i_set_a_root_password/
I like the suggestion to set the root password after first
boot:
"What I do is skip the root password in the installer and
then set one after first boot. ... The reason I use sudo
exclusively but still set a root password is because grub's
recovery console requires one."
08/10/2024 What does it mean to initialize an int?
https://herbsutter.com/2024/08/07/reader-qa-what-does-it-mean-to-initialize-an-int/
08/07/2024 Macports 2.10.0:
https://github.com/macports/macports-base/releases/tag/v2.10.0
I encountered an sqlite error that was fixed with a 'sudo port selfupdate':
https://lists.macports.org/pipermail/macports-users/2024-August/052830.html
08/06/2024 Engadget's 2024 ergonomic keyboard recommendations:
https://www.engadget.com/best-ergonomic-keyboard-130047982.html
May have to try one of these when/if my Microsoft Surface
keyboards break.
08/06/2024 MacOS Containers:
https://eclecticlight.co/2024/08/05/what-are-all-those-containers/
08/04/2024 while vs do-while:
https://craftofcoding.wordpress.com/wp-content/uploads/2024/08/roadrunnerc.png?w=600
08/04/2024 Cool aliens rock fishing hats:
https://www.reddit.com/r/Stargate/comments/1eingdv/tealc_and_spock_agree_cool_aliens_rock_fishing/
08/02/2024 Graphene found on the moon:
https://newatlas.com/materials/natural-graphene-moon-discovered/
08/02/2024 Odin could have been villain on SG-1:
https://www.gateworld.net/news/2024/08/stargate-ancient-asgard-almost-major-villain/
"But in the final balance, Stargate's writers may have made
the right decision by keeping the Asgard as our benevolent
allies - and not introducing an aggressively creepy
antagonist."
08/02/2024 Civ 7 game play premier will be on August 20:
https://www.gamingonlinux.com/2024/08/well-get-our-first-look-at-civilization-vii-on-august-20/
08/02/2024 History of common Unix commands:
https://allthingsopen.org/articles/where-unix-came-from
Older
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##/##/2023 https://srirangav.github.io/motd/2023/motd.txt
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##/##/2022 https://srirangav.github.io/motd/2022/motd.txt
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