EEVblog Electronics Community Forum

Products => Computers => Programming => Topic started by: 741 on October 18, 2019, 01:04:37 pm

Title: What is the mathematical name for a 'circle sector' applied to a 'ring'?
Post by: 741 on October 18, 2019, 01:04:37 pm
I'm drawing a graphic which is like a doughnut chart. If we call the shape between 2 concentric circles a 'ring', what is the correct term for a 'partial ring'?

(I'd like to give the relevant variables meaningful names, preferably based around mathematically correct terms)
Title: Re: What is the mathematical name for a 'circle sector' applied to a 'ring'?
Post by: Mechatrommer on October 18, 2019, 01:28:07 pm
just google "partial donut shape mathematics"
Annulus Sector (https://rechneronline.de/pi/annulus-sector.php)
Annulus (Mathematics) (https://en.wikipedia.org/wiki/Annulus_(mathematics))
Title: Re: What is the mathematical name for a 'circle sector' applied to a 'ring'?
Post by: 741 on October 18, 2019, 02:25:05 pm
OK Thanks, it seems the term is going to be "Annular Sector".
Title: Re: What is the mathematical name for a 'circle sector' applied to a 'ring'?
Post by: SiliconWizard on October 18, 2019, 02:34:36 pm
The "correct" math term would be annulus sector, but I admit this doesn't sound very appealing for some reason, so I'll concede the annular sector.
Title: Re: What is the mathematical name for a 'circle sector' applied to a 'ring'?
Post by: 741 on October 25, 2019, 08:49:15 pm
That was my intuitive feeling, but I must (now) admit "annular sector", whilst sounding nicer, is a contradiction: Like saying "circular sector". A sector cannot be itself circular or annular I suppose.
Title: Re: What is the mathematical name for a 'circle sector' applied to a 'ring'?
Post by: Nominal Animal on October 26, 2019, 03:07:03 am
I admit, the first thing that came to my mind was "sphincter".  But yeah, annulus (https://en.wikipedia.org/wiki/Annulus_(mathematics)) it is.
Title: Re: What is the mathematical name for a 'circle sector' applied to a 'ring'?
Post by: SiliconWizard on October 26, 2019, 02:27:35 pm
Quote from: 741 on October 25, 2019, 08:49:15 pm
That was my intuitive feeling, but I must (now) admit "annular sector", whilst sounding nicer, is a contradiction: Like saying "circular sector". A sector cannot be itself circular or annular I suppose.

Yeah, it didn't sound this weird to me at first (due to this not being my native language), but it is. It's not exactly a contradiction I'd say, more like a definition turned upside down.
But yeah, "annulus" frankly sounds horrible. :-DD

Even if it's probably less correct, and more informal, wouldn't "ring sector" be appropriate, and sound better?
Title: Re: What is the mathematical name for a 'circle sector' applied to a 'ring'?
Post by: SL4P on October 27, 2019, 02:06:22 am
I’ll throw ‘arc’ into the discussion!
Title: Re: What is the mathematical name for a 'circle sector' applied to a 'ring'?
Post by: Mechatrommer on October 27, 2019, 06:09:19 am
really, whats wrong with Annulus? its not like Annalus and Annalar wont solve anything... there will be always something to talk, move on!...

(http://spikedmath.com/comics/482-dirty-mathematics.png)

Quote from: SL4P on October 27, 2019, 02:06:22 am
I’ll throw ‘arc’ into the discussion!
arc is a "curvular" line of zero area. https://en.wikipedia.org/wiki/Arc_(geometry) (https://en.wikipedia.org/wiki/Arc_(geometry)) whatever