Editing Talk:2748: Radians Are Cursed

Jump to: navigation, search
Ambox notice.png Please sign your posts with ~~~~

Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.

The edit can be undone. Please check the comparison below to verify that this is what you want to do, and then save the changes below to finish undoing the edit.
Latest revision Your text
Line 31: Line 31:
 
::I mean, I'm sorry, but respectfully, you are wrong.  The unit circle is *by definition* a circle of radius 1.  There is no unit attached to that.  [[Special:Contributions/172.71.82.41|172.71.82.41]] 01:55, 13 March 2023 (UTC)
 
::I mean, I'm sorry, but respectfully, you are wrong.  The unit circle is *by definition* a circle of radius 1.  There is no unit attached to that.  [[Special:Contributions/172.71.82.41|172.71.82.41]] 01:55, 13 March 2023 (UTC)
 
:::Correction: The unit is that of the radius, ''by definition''. It is one of that unit, whatever that unit may be. You attach whatever unit you want to it, when you want to, but it isn't actually a unitless value when you start comparing it with othe values whose relationship and own unit are known. [[Special:Contributions/172.71.178.207|172.71.178.207]] 03:59, 13 March 2023 (UTC)
 
:::Correction: The unit is that of the radius, ''by definition''. It is one of that unit, whatever that unit may be. You attach whatever unit you want to it, when you want to, but it isn't actually a unitless value when you start comparing it with othe values whose relationship and own unit are known. [[Special:Contributions/172.71.178.207|172.71.178.207]] 03:59, 13 March 2023 (UTC)
::::I'd say the radius of a plain unit circle is unitless, but not dimensionless. It has a length dimension, but we don't necessarily attach a unit to that dimension. [[User:Pmc|Pmc]] ([[User talk:Pmc|talk]]) 18:19, 25 April 2023 (UTC)
 
  
 
There is actually some dispute about whether angles should be measured using units. I can't find it now, but there was an article by someone arguing that the current SI definition of the radian as 1 rad = 1 m / 1 m was flawed. He felt that units of angle should have a dimension, A, and rewrote several formulae slightly to accommodate this. But more often today, the radian is considered dimensionless with a value of exactly 1, making it not actually a "unit" so much as a hint telling how the angle was measured. In this definition, an angle has a measure of x (radians) iff the circular arc it intercepts as a central angle has an arclength of x times the circle's radius. Under this definition, the following become mathematically correct:
 
There is actually some dispute about whether angles should be measured using units. I can't find it now, but there was an article by someone arguing that the current SI definition of the radian as 1 rad = 1 m / 1 m was flawed. He felt that units of angle should have a dimension, A, and rewrote several formulae slightly to accommodate this. But more often today, the radian is considered dimensionless with a value of exactly 1, making it not actually a "unit" so much as a hint telling how the angle was measured. In this definition, an angle has a measure of x (radians) iff the circular arc it intercepts as a central angle has an arclength of x times the circle's radius. Under this definition, the following become mathematically correct:

Please note that all contributions to explain xkcd may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here.
You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see explain xkcd:Copyrights for details). Do not submit copyrighted work without permission!

To protect the wiki against automated edit spam, we kindly ask you to solve the following CAPTCHA:

Cancel | Editing help (opens in new window)

Template used on this page: