frontpage.
newsnewestaskshowjobs

Made with ♥ by @iamnishanth

Open Source @Github

fp.

Open in hackernews

Avoiding Trigonometry (2013)

https://iquilezles.org/articles/noacos/
30•WithinReason•2h ago

Comments

srean•52m ago
This has been some sort of a mix of peeve and a moment of enlightenment of mine when I understood this.

I wholeheartedly agree with the point being made in the post. I had commented about this in the recent asin() post but deleted thinking it might not be of general interest.

If you care about angles and rotations in the plane, it is often profitable to represent an angle not by a scalar such as a degree or a radian but as a tuple

    (cos \theta, sin \theta)
or as a complex number.

This way one can often avoid calls to expensive trigonometric functions. One may need calls to square roots and general polynomial root finding.

In Python you can represent an angle as a unit complex numbers and the runtime will do the computations for you.

For example, if you needed the angular bisector of an angle subtended at the origin (you can translate the vertex there and later undo the translation), the bisector is just the geometric mean of the arms of the angle

   sqrt(z1 * z2)
Along with stereographic transform and its inverse you can do a lot.

This is directly related to the field of algebraic numbers.

With complex numbers you get translations, scaled rotations and reflections. Sufficient for Euclidean geometry.

chriswarbo•31m ago
Norman Wildberger takes this to the extreme with Rational Trigonometry https://en.wikipedia.org/wiki/Divine_Proportions:_Rational_T...

It eschews angles entirely, sticking to ratios. It avoids square roots by sticking to "quadrances" (squared distance; i.e. pythagoras/euclidean-distance without taking square roots).

I highly recommend Wildberger's extensive Youtube channels too https://www.youtube.com/@njwildberger and https://www.youtube.com/@WildEggmathematicscourses

He's quite contrarian, so I'd take his informal statements with a pinch of salt (e.g. that there's no such thing as Real numbers; the underlying argument is reasonable, but the grand statements lose all that nuance); but he ends up approaching many subjects from an interesting perspective, and presents lots of nice connections e.g. between projective geometry, linear algebra, etc.

srean•30m ago
He maybe considered contrarian but his math is sound.
storus•28m ago
In principle, wouldn't a change of basis be all that is needed?
srean•25m ago
It's a little more than change of basis, although change of basis is an important part of it. It converts many apparently trigonometric operations into algebraic ones, root finding included.

There are certain drawbacks. If the solution involves non-algebraic numbers there is no getting away from the transcendental numbers (that ultimately get approximated by algebraic numbers).

The Billionaires' War

https://paulkrugman.substack.com/p/the-billionaires-war
1•xqcgrek2•2m ago•0 comments

A quirk of relativity is the closest thing to achieving immortality

https://bigthink.com/starts-with-a-bang/relativity-physics-immortality/
1•Brajeshwar•3m ago•0 comments

Using AI to make an app that will cut fret slots

https://www.youtube.com/watch?v=4xS-GUuyw2o
1•seesthruya•3m ago•1 comments

Show HN: Elevators.ltd

https://elevators.ltd
2•pkstn•4m ago•0 comments

Show HN: SpotVortex helps SRE teams push more Kubernetes capacity onto Spot

https://github.com/softcane/spot-vortex-agent
1•softcane•4m ago•0 comments

Cutile.jl Brings Nvidia CUDA Tile-Based Programming to Julia

https://developer.nvidia.com/blog/cutile-jl-brings-nvidia-cuda-tile-based-programming-to-julia/
1•pjmlp•5m ago•0 comments

IconPilot – search and customize SVG icons instantly while building UI

https://www.iconpilot.app/
1•mlmoreno•5m ago•1 comments

AI Agent Security: Authentication, Tool Access, and Defense in Depth

https://chatbotkit.com/guides/ai-agent-security-guide
1•_pdp_•7m ago•0 comments

Why Falling Cats Always Seem to Land on Their Feet

https://www.nytimes.com/2026/03/11/science/falling-cat-problem.html
1•breve•9m ago•0 comments

Is MCP Dead?

https://medium.com/@flamehaven/is-mcp-really-dead-a-history-of-ai-hype-told-through-the-rise-and-...
1•interpol_p•10m ago•0 comments

OBS Studio 32.1 Released with WebRTC Simulcast Support

https://www.phoronix.com/news/OBS-Studio-32.1-Released
2•mikece•12m ago•0 comments

NVIDIA Nemotron 3 Super

https://twitter.com/ctnzr/status/2031762077325406428
2•tosh•15m ago•0 comments

Solid Wood Legs: Maximum Stability for Top-Heavy Mirror Units

https://dreamhomestore.co.uk/collections/dressing-tables
1•johnfloyd2k9•15m ago•1 comments

Iran appears to have conducted a significant cyberattack against a U.S. company

https://www.nbcnews.com/world/iran/iran-appears-conducted-significant-cyberattack-us-company-firs...
4•chrisjj•17m ago•1 comments

Show HN: Detect when an LLM silently changes behavior for the same prompt

https://github.com/aelitium-dev/aelitium-v3
1•catarina_eng•18m ago•2 comments

Top news shared by the people you trust

https://sill.social
1•doener•19m ago•0 comments

1968 My Lai Massacre

https://en.wikipedia.org/wiki/My_Lai_massacre
2•simonebrunozzi•21m ago•0 comments

What Happened to A2A Protocol?

https://www.credal.ai/blog/what-happened-to-a2a-protocol
1•makaimc•23m ago•0 comments

Show HN: I built a screen recorder with automatic zoom effects

https://rookieclip.com/
2•this-is-shreya•26m ago•3 comments

Microsoft adding Xbox mode to Windows 11

https://www.theregister.com/2026/03/12/xbox_mode_windows_11/
3•Brajeshwar•28m ago•1 comments

Show HN: MeepaChat – Slack for AI Agents (iOS, macOS, Web / Cloud, Self-Hosted)

https://github.com/bogpad/meepachat
2•beasubs•30m ago•1 comments

Addressing GitHub's recent availability issues

https://github.blog/news-insights/company-news/addressing-githubs-recent-availability-issues-2/
1•mvcosta91•31m ago•0 comments

Show HN: VmExit – an experiment in AI-native computing

https://vmexit.dev
2•bgleb•31m ago•0 comments

Generic Tech Company Art Style Woman Devouring Her Son (2021)

https://jemima.design.blog/2021/02/08/generic-tech-company-art-style-woman-devouring-her-son/
1•darkwater•33m ago•0 comments

Hurdles of Migrating from Discord to self hosted Matrix

https://www.310networks.com/posts/moving-from-discord-to-selfhosted-matrix/
2•kookster310•35m ago•0 comments

Wegovy may have highest 'eye stroke' and sight loss risk of GLP-1 agonists

https://bmjgroup.com/wegovy-may-have-highest-eye-stroke-and-sight-loss-risk-of-semaglutide-glp-1-...
2•giuliomagnifico•36m ago•0 comments

SlackClaw: OpenClaw Slack Intergration in One Click

https://www.slackclaw.ai
1•saroyas•40m ago•3 comments

Claude 4.6 Opus can recite Linux's list.h

4•itzmetanjim•40m ago•0 comments

Infinitely Recursive Game of Life

https://oimo.io/works/life/
1•marvinborner•42m ago•0 comments

What If Iceland Freezes Over?

https://newsletter-cdn.europeancorrespondent.com/go/vmztjo18oddwailb7esghf598bqlk8mwxv5wgo4gc17v/...
2•donohoe•42m ago•0 comments