Why are X and Y commonly used as mathematical placeholders?
$begingroup$
I realize that X and Y are relatively popular terms when wanting to use a placeholder for an unknown English or math term. What is the origin of this term, and why was it X and Y; why not the other letters?
notation
asked Dec 27 '18 at 19:03
Sweet_CherrySweet_Cherry
33426
$endgroup$
migrated from english.stackexchange.com Dec 28 '18 at 18:35
This question came from our site for linguists, etymologists, and serious English language enthusiasts.
|
show 1 more comment
$begingroup$
I realize that X and Y are relatively popular terms when wanting to use a placeholder for an unknown English or math term. What is the origin of this term, and why was it X and Y; why not the other letters?
notation
asked Dec 27 '18 at 19:03
Sweet_CherrySweet_Cherry
33426
$endgroup$
migrated from english.stackexchange.com Dec 28 '18 at 18:35
This question came from our site for linguists, etymologists, and serious English language enthusiasts.
1
$begingroup$
May I ask why this is off-topic or unclear?
$endgroup$
– Sweet_Cherry
Dec 30 '18 at 18:14
$begingroup$
I was somewhat put off by the migration from ELU to here, but the word mathematical was finally added. However, after looking up placeholder it seems to only have two general definitions. It has the obvious math one that we all know. But there's also some (academic?) linguistic definition that I don't quite understand. Regardless, what I cannot find is what I thought it meant, which is what one might assume place holder means. IMO: a stand-in (which is about people; n/a) - tl;dr: I can't find a definition of placeholder in reference to a physical object, which is surprising.
$endgroup$
– Mazura
Dec 30 '18 at 23:23
$begingroup$
@Mazura Originally I posted it on ELU because most people were using X and Y in their questions. I was aware that it was used in math (obviously), but I wasn't aware of this S.E. By placeholder, I mean an unknown number/word.
$endgroup$
– Sweet_Cherry
Dec 30 '18 at 23:26
$begingroup$
With the addition of mathematical I don't see how it could be anymore on-topic or anymore clear. And unfortunately, any less the question that I actually wanted answered: When was X first used as a substitute for a given object or person, with an unknown quantity or quality?
$endgroup$
– Mazura
Dec 30 '18 at 23:28
1
$begingroup$
Because a and b are busy being a) used elsewhere and b) to denote alternatives
$endgroup$
– Valorum
Dec 31 '18 at 10:27
|
show 1 more comment
$begingroup$
I realize that X and Y are relatively popular terms when wanting to use a placeholder for an unknown English or math term. What is the origin of this term, and why was it X and Y; why not the other letters?
notation
asked Dec 27 '18 at 19:03
Sweet_CherrySweet_Cherry
33426
$endgroup$
I realize that X and Y are relatively popular terms when wanting to use a placeholder for an unknown English or math term. What is the origin of this term, and why was it X and Y; why not the other letters?
notation
notation
asked Dec 27 '18 at 19:03
Sweet_CherrySweet_Cherry
33426
asked Dec 27 '18 at 19:03
Sweet_CherrySweet_Cherry
33426
edited Dec 30 '18 at 19:57
Sweet_Cherry
asked Dec 27 '18 at 19:03
Sweet_CherrySweet_Cherry
33426
asked Dec 27 '18 at 19:03
Sweet_CherrySweet_Cherry
33426
asked Dec 27 '18 at 19:03
Sweet_CherrySweet_Cherry
33426
33426
migrated from english.stackexchange.com Dec 28 '18 at 18:35
This question came from our site for linguists, etymologists, and serious English language enthusiasts.
migrated from english.stackexchange.com Dec 28 '18 at 18:35
This question came from our site for linguists, etymologists, and serious English language enthusiasts.
1
$begingroup$
May I ask why this is off-topic or unclear?
$endgroup$
– Sweet_Cherry
Dec 30 '18 at 18:14
$begingroup$
I was somewhat put off by the migration from ELU to here, but the word mathematical was finally added. However, after looking up placeholder it seems to only have two general definitions. It has the obvious math one that we all know. But there's also some (academic?) linguistic definition that I don't quite understand. Regardless, what I cannot find is what I thought it meant, which is what one might assume place holder means. IMO: a stand-in (which is about people; n/a) - tl;dr: I can't find a definition of placeholder in reference to a physical object, which is surprising.
$endgroup$
– Mazura
Dec 30 '18 at 23:23
$begingroup$
@Mazura Originally I posted it on ELU because most people were using X and Y in their questions. I was aware that it was used in math (obviously), but I wasn't aware of this S.E. By placeholder, I mean an unknown number/word.
$endgroup$
– Sweet_Cherry
Dec 30 '18 at 23:26
$begingroup$
With the addition of mathematical I don't see how it could be anymore on-topic or anymore clear. And unfortunately, any less the question that I actually wanted answered: When was X first used as a substitute for a given object or person, with an unknown quantity or quality?
$endgroup$
– Mazura
Dec 30 '18 at 23:28
1
$begingroup$
Because a and b are busy being a) used elsewhere and b) to denote alternatives
$endgroup$
– Valorum
Dec 31 '18 at 10:27
|
show 1 more comment
1
$begingroup$
May I ask why this is off-topic or unclear?
$endgroup$
– Sweet_Cherry
Dec 30 '18 at 18:14
$begingroup$
I was somewhat put off by the migration from ELU to here, but the word mathematical was finally added. However, after looking up placeholder it seems to only have two general definitions. It has the obvious math one that we all know. But there's also some (academic?) linguistic definition that I don't quite understand. Regardless, what I cannot find is what I thought it meant, which is what one might assume place holder means. IMO: a stand-in (which is about people; n/a) - tl;dr: I can't find a definition of placeholder in reference to a physical object, which is surprising.
$endgroup$
– Mazura
Dec 30 '18 at 23:23
$begingroup$
@Mazura Originally I posted it on ELU because most people were using X and Y in their questions. I was aware that it was used in math (obviously), but I wasn't aware of this S.E. By placeholder, I mean an unknown number/word.
$endgroup$
– Sweet_Cherry
Dec 30 '18 at 23:26
$begingroup$
With the addition of mathematical I don't see how it could be anymore on-topic or anymore clear. And unfortunately, any less the question that I actually wanted answered: When was X first used as a substitute for a given object or person, with an unknown quantity or quality?
$endgroup$
– Mazura
Dec 30 '18 at 23:28
1
$begingroup$
Because a and b are busy being a) used elsewhere and b) to denote alternatives
$endgroup$
– Valorum
Dec 31 '18 at 10:27
1
1
$begingroup$
May I ask why this is off-topic or unclear?
$endgroup$
– Sweet_Cherry
Dec 30 '18 at 18:14
$begingroup$
May I ask why this is off-topic or unclear?
$endgroup$
– Sweet_Cherry
Dec 30 '18 at 18:14
$begingroup$
I was somewhat put off by the migration from ELU to here, but the word mathematical was finally added. However, after looking up placeholder it seems to only have two general definitions. It has the obvious math one that we all know. But there's also some (academic?) linguistic definition that I don't quite understand. Regardless, what I cannot find is what I thought it meant, which is what one might assume place holder means. IMO: a stand-in (which is about people; n/a) - tl;dr: I can't find a definition of placeholder in reference to a physical object, which is surprising.
$endgroup$
– Mazura
Dec 30 '18 at 23:23
$begingroup$
I was somewhat put off by the migration from ELU to here, but the word mathematical was finally added. However, after looking up placeholder it seems to only have two general definitions. It has the obvious math one that we all know. But there's also some (academic?) linguistic definition that I don't quite understand. Regardless, what I cannot find is what I thought it meant, which is what one might assume place holder means. IMO: a stand-in (which is about people; n/a) - tl;dr: I can't find a definition of placeholder in reference to a physical object, which is surprising.
$endgroup$
– Mazura
Dec 30 '18 at 23:23
$begingroup$
@Mazura Originally I posted it on ELU because most people were using X and Y in their questions. I was aware that it was used in math (obviously), but I wasn't aware of this S.E. By placeholder, I mean an unknown number/word.
$endgroup$
– Sweet_Cherry
Dec 30 '18 at 23:26
$begingroup$
@Mazura Originally I posted it on ELU because most people were using X and Y in their questions. I was aware that it was used in math (obviously), but I wasn't aware of this S.E. By placeholder, I mean an unknown number/word.
$endgroup$
– Sweet_Cherry
Dec 30 '18 at 23:26
$begingroup$
With the addition of mathematical I don't see how it could be anymore on-topic or anymore clear. And unfortunately, any less the question that I actually wanted answered: When was X first used as a substitute for a given object or person, with an unknown quantity or quality?
$endgroup$
– Mazura
Dec 30 '18 at 23:28
$begingroup$
With the addition of mathematical I don't see how it could be anymore on-topic or anymore clear. And unfortunately, any less the question that I actually wanted answered: When was X first used as a substitute for a given object or person, with an unknown quantity or quality?
$endgroup$
– Mazura
Dec 30 '18 at 23:28
1
1
$begingroup$
Because a and b are busy being a) used elsewhere and b) to denote alternatives
$endgroup$
– Valorum
Dec 31 '18 at 10:27
$begingroup$
Because a and b are busy being a) used elsewhere and b) to denote alternatives
$endgroup$
– Valorum
Dec 31 '18 at 10:27
|
show 1 more comment
3 Answers
3
active
oldest
votes
$begingroup$
They became popular because of René Descartes’ usage in his La Géométrie. The letters at the end of the alphabet are chosen as the variables, while those at the beginning are constants. There is speculation about why this might have been done. It is likely to allow the largest number of sequential letters without overlap between the two sets.
Why x became the most common is unknown. Some sources attempt to draw a line from the Arabic word for unknown through the Greek letter chi (which resembles a capital X), but the claims are unsubstantiated (Arabic being the source of our numerals and Greek being the common letter set for variables).
The link from mathematics to common speech is likely just a simple repurposing of known concepts.
$endgroup$
$begingroup$
It seems the obvious choice as, X is what you make your mark with. But when's that from, cuneiform?
$endgroup$
– Mazura
Dec 28 '18 at 0:32
$begingroup$
Oh possibly. As crossed lines are the simplest way to mark an exact point on a map, this was also likely used far before cuneiform, even. However, the usage of “x” in the place of an arbitrary or unknown didn’t rise before Descartes popularized it.
$endgroup$
– Ian MacDonald
Dec 28 '18 at 0:46
$begingroup$
What is the origin of the phrase “Leave your Mark”? - Well, I think X already was the most common, 'variable' so to speak, but why he chose it is speculative. (Just how common it was to draw a picture instead of signing an X, IDK...)
$endgroup$
– Mazura
Dec 28 '18 at 1:02
1
$begingroup$
Have you watched this Ted talk given by Terry Moore on why X is the unknown? ted.com/talks/terry_moore_why_is_x_the_unknown/…
$endgroup$
– Equinox
Dec 28 '18 at 8:22
1
$begingroup$
I have read the transcript and the proposal made is weak at best.
$endgroup$
– Ian MacDonald
Dec 28 '18 at 13:22
|
show 3 more comments
$begingroup$
See Earliest uses of mathematical symbols, which quotes
F. Cajori, A History of Mathematical Notations, 2 volumes (1928-29)
The use of z, y, x ... to represent unknowns is due to René Descartes, in his La géometrie (1637). Without comment, he introduces the use of the first letters of the alphabet to signify known quantities and the use of the last letters to signify unknown quantities.
answered Dec 27 '18 at 19:31
Gerald EdgarGerald Edgar
4,1401719
$endgroup$
1
$begingroup$
It's fascinating how much influence one person can have. I wonder what René would say today if he saw x as variable name splattered all over classrooms worldwide, journals, whiteboards, labs, computer code...
$endgroup$
– Lightness Races in Orbit
Dec 28 '18 at 1:17
4
$begingroup$
@LightnessRacesinOrbit he'd likely be happy that people agreed on a consistent naming convention and flattered that it was his that they chose.
$endgroup$
– The Great Duck
Dec 28 '18 at 4:40
add a comment |
$begingroup$
Here is the original source : René Descartes, La Géométrie (1637), I, page 299, for $a,b$ used to denote parameters.
And see I, page 301 for $z$ and I, page 303 for $x,y$ respectively, used to refer to an unknown quantity.
Letters was already used by François Viète (but the use of alphabetical variables to represent magnitudes is due to euclidean geometry).
See In artem analyticem isagoge (1591), Rule III :
Sunto duae magnitudines $A$ & $B$. [Let there be two magnitudes, $A$ and $B$.]
And also :
Oportet $A dfrac {text { plano }}{B}$ addere $Z$ [Suppose $Z$ is to be added to $A^p / B$].
But obviously the success of Descartes' "new geometry" explains the success of the new algebraic notation.
answered Dec 29 '18 at 10:19
Mauro ALLEGRANZAMauro ALLEGRANZA
11.6k11939
$endgroup$
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "587"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fhsm.stackexchange.com%2fquestions%2f8109%2fwhy-are-x-and-y-commonly-used-as-mathematical-placeholders%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
They became popular because of René Descartes’ usage in his La Géométrie. The letters at the end of the alphabet are chosen as the variables, while those at the beginning are constants. There is speculation about why this might have been done. It is likely to allow the largest number of sequential letters without overlap between the two sets.
Why x became the most common is unknown. Some sources attempt to draw a line from the Arabic word for unknown through the Greek letter chi (which resembles a capital X), but the claims are unsubstantiated (Arabic being the source of our numerals and Greek being the common letter set for variables).
The link from mathematics to common speech is likely just a simple repurposing of known concepts.
$endgroup$
$begingroup$
It seems the obvious choice as, X is what you make your mark with. But when's that from, cuneiform?
$endgroup$
– Mazura
Dec 28 '18 at 0:32
$begingroup$
Oh possibly. As crossed lines are the simplest way to mark an exact point on a map, this was also likely used far before cuneiform, even. However, the usage of “x” in the place of an arbitrary or unknown didn’t rise before Descartes popularized it.
$endgroup$
– Ian MacDonald
Dec 28 '18 at 0:46
$begingroup$
What is the origin of the phrase “Leave your Mark”? - Well, I think X already was the most common, 'variable' so to speak, but why he chose it is speculative. (Just how common it was to draw a picture instead of signing an X, IDK...)
$endgroup$
– Mazura
Dec 28 '18 at 1:02
1
$begingroup$
Have you watched this Ted talk given by Terry Moore on why X is the unknown? ted.com/talks/terry_moore_why_is_x_the_unknown/…
$endgroup$
– Equinox
Dec 28 '18 at 8:22
1
$begingroup$
I have read the transcript and the proposal made is weak at best.
$endgroup$
– Ian MacDonald
Dec 28 '18 at 13:22
|
show 3 more comments
$begingroup$
They became popular because of René Descartes’ usage in his La Géométrie. The letters at the end of the alphabet are chosen as the variables, while those at the beginning are constants. There is speculation about why this might have been done. It is likely to allow the largest number of sequential letters without overlap between the two sets.
Why x became the most common is unknown. Some sources attempt to draw a line from the Arabic word for unknown through the Greek letter chi (which resembles a capital X), but the claims are unsubstantiated (Arabic being the source of our numerals and Greek being the common letter set for variables).
The link from mathematics to common speech is likely just a simple repurposing of known concepts.
$endgroup$
$begingroup$
It seems the obvious choice as, X is what you make your mark with. But when's that from, cuneiform?
$endgroup$
– Mazura
Dec 28 '18 at 0:32
$begingroup$
Oh possibly. As crossed lines are the simplest way to mark an exact point on a map, this was also likely used far before cuneiform, even. However, the usage of “x” in the place of an arbitrary or unknown didn’t rise before Descartes popularized it.
$endgroup$
– Ian MacDonald
Dec 28 '18 at 0:46
$begingroup$
What is the origin of the phrase “Leave your Mark”? - Well, I think X already was the most common, 'variable' so to speak, but why he chose it is speculative. (Just how common it was to draw a picture instead of signing an X, IDK...)
$endgroup$
– Mazura
Dec 28 '18 at 1:02
1
$begingroup$
Have you watched this Ted talk given by Terry Moore on why X is the unknown? ted.com/talks/terry_moore_why_is_x_the_unknown/…
$endgroup$
– Equinox
Dec 28 '18 at 8:22
1
$begingroup$
I have read the transcript and the proposal made is weak at best.
$endgroup$
– Ian MacDonald
Dec 28 '18 at 13:22
|
show 3 more comments
$begingroup$
They became popular because of René Descartes’ usage in his La Géométrie. The letters at the end of the alphabet are chosen as the variables, while those at the beginning are constants. There is speculation about why this might have been done. It is likely to allow the largest number of sequential letters without overlap between the two sets.
Why x became the most common is unknown. Some sources attempt to draw a line from the Arabic word for unknown through the Greek letter chi (which resembles a capital X), but the claims are unsubstantiated (Arabic being the source of our numerals and Greek being the common letter set for variables).
The link from mathematics to common speech is likely just a simple repurposing of known concepts.
$endgroup$
They became popular because of René Descartes’ usage in his La Géométrie. The letters at the end of the alphabet are chosen as the variables, while those at the beginning are constants. There is speculation about why this might have been done. It is likely to allow the largest number of sequential letters without overlap between the two sets.
Why x became the most common is unknown. Some sources attempt to draw a line from the Arabic word for unknown through the Greek letter chi (which resembles a capital X), but the claims are unsubstantiated (Arabic being the source of our numerals and Greek being the common letter set for variables).
The link from mathematics to common speech is likely just a simple repurposing of known concepts.
answered Dec 27 '18 at 19:26
Ian MacDonald
$begingroup$
It seems the obvious choice as, X is what you make your mark with. But when's that from, cuneiform?
$endgroup$
– Mazura
Dec 28 '18 at 0:32
$begingroup$
Oh possibly. As crossed lines are the simplest way to mark an exact point on a map, this was also likely used far before cuneiform, even. However, the usage of “x” in the place of an arbitrary or unknown didn’t rise before Descartes popularized it.
$endgroup$
– Ian MacDonald
Dec 28 '18 at 0:46
$begingroup$
What is the origin of the phrase “Leave your Mark”? - Well, I think X already was the most common, 'variable' so to speak, but why he chose it is speculative. (Just how common it was to draw a picture instead of signing an X, IDK...)
$endgroup$
– Mazura
Dec 28 '18 at 1:02
1
$begingroup$
Have you watched this Ted talk given by Terry Moore on why X is the unknown? ted.com/talks/terry_moore_why_is_x_the_unknown/…
$endgroup$
– Equinox
Dec 28 '18 at 8:22
1
$begingroup$
I have read the transcript and the proposal made is weak at best.
$endgroup$
– Ian MacDonald
Dec 28 '18 at 13:22
|
show 3 more comments
$begingroup$
It seems the obvious choice as, X is what you make your mark with. But when's that from, cuneiform?
$endgroup$
– Mazura
Dec 28 '18 at 0:32
$begingroup$
Oh possibly. As crossed lines are the simplest way to mark an exact point on a map, this was also likely used far before cuneiform, even. However, the usage of “x” in the place of an arbitrary or unknown didn’t rise before Descartes popularized it.
$endgroup$
– Ian MacDonald
Dec 28 '18 at 0:46
$begingroup$
What is the origin of the phrase “Leave your Mark”? - Well, I think X already was the most common, 'variable' so to speak, but why he chose it is speculative. (Just how common it was to draw a picture instead of signing an X, IDK...)
$endgroup$
– Mazura
Dec 28 '18 at 1:02
1
$begingroup$
Have you watched this Ted talk given by Terry Moore on why X is the unknown? ted.com/talks/terry_moore_why_is_x_the_unknown/…
$endgroup$
– Equinox
Dec 28 '18 at 8:22
1
$begingroup$
I have read the transcript and the proposal made is weak at best.
$endgroup$
– Ian MacDonald
Dec 28 '18 at 13:22
$begingroup$
It seems the obvious choice as, X is what you make your mark with. But when's that from, cuneiform?
$endgroup$
– Mazura
Dec 28 '18 at 0:32
$begingroup$
It seems the obvious choice as, X is what you make your mark with. But when's that from, cuneiform?
$endgroup$
– Mazura
Dec 28 '18 at 0:32
$begingroup$
Oh possibly. As crossed lines are the simplest way to mark an exact point on a map, this was also likely used far before cuneiform, even. However, the usage of “x” in the place of an arbitrary or unknown didn’t rise before Descartes popularized it.
$endgroup$
– Ian MacDonald
Dec 28 '18 at 0:46
$begingroup$
Oh possibly. As crossed lines are the simplest way to mark an exact point on a map, this was also likely used far before cuneiform, even. However, the usage of “x” in the place of an arbitrary or unknown didn’t rise before Descartes popularized it.
$endgroup$
– Ian MacDonald
Dec 28 '18 at 0:46
$begingroup$
What is the origin of the phrase “Leave your Mark”? - Well, I think X already was the most common, 'variable' so to speak, but why he chose it is speculative. (Just how common it was to draw a picture instead of signing an X, IDK...)
$endgroup$
– Mazura
Dec 28 '18 at 1:02
$begingroup$
What is the origin of the phrase “Leave your Mark”? - Well, I think X already was the most common, 'variable' so to speak, but why he chose it is speculative. (Just how common it was to draw a picture instead of signing an X, IDK...)
$endgroup$
– Mazura
Dec 28 '18 at 1:02
1
1
$begingroup$
Have you watched this Ted talk given by Terry Moore on why X is the unknown? ted.com/talks/terry_moore_why_is_x_the_unknown/…
$endgroup$
– Equinox
Dec 28 '18 at 8:22
$begingroup$
Have you watched this Ted talk given by Terry Moore on why X is the unknown? ted.com/talks/terry_moore_why_is_x_the_unknown/…
$endgroup$
– Equinox
Dec 28 '18 at 8:22
1
1
$begingroup$
I have read the transcript and the proposal made is weak at best.
$endgroup$
– Ian MacDonald
Dec 28 '18 at 13:22
$begingroup$
I have read the transcript and the proposal made is weak at best.
$endgroup$
– Ian MacDonald
Dec 28 '18 at 13:22
|
show 3 more comments
$begingroup$
See Earliest uses of mathematical symbols, which quotes
F. Cajori, A History of Mathematical Notations, 2 volumes (1928-29)
The use of z, y, x ... to represent unknowns is due to René Descartes, in his La géometrie (1637). Without comment, he introduces the use of the first letters of the alphabet to signify known quantities and the use of the last letters to signify unknown quantities.
answered Dec 27 '18 at 19:31
Gerald EdgarGerald Edgar
4,1401719
$endgroup$
1
$begingroup$
It's fascinating how much influence one person can have. I wonder what René would say today if he saw x as variable name splattered all over classrooms worldwide, journals, whiteboards, labs, computer code...
$endgroup$
– Lightness Races in Orbit
Dec 28 '18 at 1:17
4
$begingroup$
@LightnessRacesinOrbit he'd likely be happy that people agreed on a consistent naming convention and flattered that it was his that they chose.
$endgroup$
– The Great Duck
Dec 28 '18 at 4:40
add a comment |
$begingroup$
See Earliest uses of mathematical symbols, which quotes
F. Cajori, A History of Mathematical Notations, 2 volumes (1928-29)
The use of z, y, x ... to represent unknowns is due to René Descartes, in his La géometrie (1637). Without comment, he introduces the use of the first letters of the alphabet to signify known quantities and the use of the last letters to signify unknown quantities.
answered Dec 27 '18 at 19:31
Gerald EdgarGerald Edgar
4,1401719
$endgroup$
1
$begingroup$
It's fascinating how much influence one person can have. I wonder what René would say today if he saw x as variable name splattered all over classrooms worldwide, journals, whiteboards, labs, computer code...
$endgroup$
– Lightness Races in Orbit
Dec 28 '18 at 1:17
4
$begingroup$
@LightnessRacesinOrbit he'd likely be happy that people agreed on a consistent naming convention and flattered that it was his that they chose.
$endgroup$
– The Great Duck
Dec 28 '18 at 4:40
add a comment |
$begingroup$
See Earliest uses of mathematical symbols, which quotes
F. Cajori, A History of Mathematical Notations, 2 volumes (1928-29)
The use of z, y, x ... to represent unknowns is due to René Descartes, in his La géometrie (1637). Without comment, he introduces the use of the first letters of the alphabet to signify known quantities and the use of the last letters to signify unknown quantities.
answered Dec 27 '18 at 19:31
Gerald EdgarGerald Edgar
4,1401719
$endgroup$
See Earliest uses of mathematical symbols, which quotes
F. Cajori, A History of Mathematical Notations, 2 volumes (1928-29)
The use of z, y, x ... to represent unknowns is due to René Descartes, in his La géometrie (1637). Without comment, he introduces the use of the first letters of the alphabet to signify known quantities and the use of the last letters to signify unknown quantities.
answered Dec 27 '18 at 19:31
Gerald EdgarGerald Edgar
4,1401719
answered Dec 27 '18 at 19:31
Gerald EdgarGerald Edgar
4,1401719
answered Dec 27 '18 at 19:31
Gerald EdgarGerald Edgar
4,1401719
answered Dec 27 '18 at 19:31
Gerald EdgarGerald Edgar
4,1401719
4,1401719
1
$begingroup$
It's fascinating how much influence one person can have. I wonder what René would say today if he saw x as variable name splattered all over classrooms worldwide, journals, whiteboards, labs, computer code...
$endgroup$
– Lightness Races in Orbit
Dec 28 '18 at 1:17
4
$begingroup$
@LightnessRacesinOrbit he'd likely be happy that people agreed on a consistent naming convention and flattered that it was his that they chose.
$endgroup$
– The Great Duck
Dec 28 '18 at 4:40
add a comment |
1
$begingroup$
It's fascinating how much influence one person can have. I wonder what René would say today if he saw x as variable name splattered all over classrooms worldwide, journals, whiteboards, labs, computer code...
$endgroup$
– Lightness Races in Orbit
Dec 28 '18 at 1:17
4
$begingroup$
@LightnessRacesinOrbit he'd likely be happy that people agreed on a consistent naming convention and flattered that it was his that they chose.
$endgroup$
– The Great Duck
Dec 28 '18 at 4:40
1
1
$begingroup$
It's fascinating how much influence one person can have. I wonder what René would say today if he saw x as variable name splattered all over classrooms worldwide, journals, whiteboards, labs, computer code...
$endgroup$
– Lightness Races in Orbit
Dec 28 '18 at 1:17
$begingroup$
It's fascinating how much influence one person can have. I wonder what René would say today if he saw x as variable name splattered all over classrooms worldwide, journals, whiteboards, labs, computer code...
$endgroup$
– Lightness Races in Orbit
Dec 28 '18 at 1:17
4
4
$begingroup$
@LightnessRacesinOrbit he'd likely be happy that people agreed on a consistent naming convention and flattered that it was his that they chose.
$endgroup$
– The Great Duck
Dec 28 '18 at 4:40
$begingroup$
@LightnessRacesinOrbit he'd likely be happy that people agreed on a consistent naming convention and flattered that it was his that they chose.
$endgroup$
– The Great Duck
Dec 28 '18 at 4:40
add a comment |
$begingroup$
Here is the original source : René Descartes, La Géométrie (1637), I, page 299, for $a,b$ used to denote parameters.
And see I, page 301 for $z$ and I, page 303 for $x,y$ respectively, used to refer to an unknown quantity.
Letters was already used by François Viète (but the use of alphabetical variables to represent magnitudes is due to euclidean geometry).
See In artem analyticem isagoge (1591), Rule III :
Sunto duae magnitudines $A$ & $B$. [Let there be two magnitudes, $A$ and $B$.]
And also :
Oportet $A dfrac {text { plano }}{B}$ addere $Z$ [Suppose $Z$ is to be added to $A^p / B$].
But obviously the success of Descartes' "new geometry" explains the success of the new algebraic notation.
answered Dec 29 '18 at 10:19
Mauro ALLEGRANZAMauro ALLEGRANZA
11.6k11939
$endgroup$
add a comment |
$begingroup$
Here is the original source : René Descartes, La Géométrie (1637), I, page 299, for $a,b$ used to denote parameters.
And see I, page 301 for $z$ and I, page 303 for $x,y$ respectively, used to refer to an unknown quantity.
Letters was already used by François Viète (but the use of alphabetical variables to represent magnitudes is due to euclidean geometry).
See In artem analyticem isagoge (1591), Rule III :
Sunto duae magnitudines $A$ & $B$. [Let there be two magnitudes, $A$ and $B$.]
And also :
Oportet $A dfrac {text { plano }}{B}$ addere $Z$ [Suppose $Z$ is to be added to $A^p / B$].
But obviously the success of Descartes' "new geometry" explains the success of the new algebraic notation.
answered Dec 29 '18 at 10:19
Mauro ALLEGRANZAMauro ALLEGRANZA
11.6k11939
$endgroup$
add a comment |
$begingroup$
Here is the original source : René Descartes, La Géométrie (1637), I, page 299, for $a,b$ used to denote parameters.
And see I, page 301 for $z$ and I, page 303 for $x,y$ respectively, used to refer to an unknown quantity.
Letters was already used by François Viète (but the use of alphabetical variables to represent magnitudes is due to euclidean geometry).
See In artem analyticem isagoge (1591), Rule III :
Sunto duae magnitudines $A$ & $B$. [Let there be two magnitudes, $A$ and $B$.]
And also :
Oportet $A dfrac {text { plano }}{B}$ addere $Z$ [Suppose $Z$ is to be added to $A^p / B$].
But obviously the success of Descartes' "new geometry" explains the success of the new algebraic notation.
answered Dec 29 '18 at 10:19
Mauro ALLEGRANZAMauro ALLEGRANZA
11.6k11939
$endgroup$
Here is the original source : René Descartes, La Géométrie (1637), I, page 299, for $a,b$ used to denote parameters.
And see I, page 301 for $z$ and I, page 303 for $x,y$ respectively, used to refer to an unknown quantity.
Letters was already used by François Viète (but the use of alphabetical variables to represent magnitudes is due to euclidean geometry).
See In artem analyticem isagoge (1591), Rule III :
Sunto duae magnitudines $A$ & $B$. [Let there be two magnitudes, $A$ and $B$.]
And also :
Oportet $A dfrac {text { plano }}{B}$ addere $Z$ [Suppose $Z$ is to be added to $A^p / B$].
But obviously the success of Descartes' "new geometry" explains the success of the new algebraic notation.
answered Dec 29 '18 at 10:19
Mauro ALLEGRANZAMauro ALLEGRANZA
11.6k11939
edited Dec 29 '18 at 12:10
answered Dec 29 '18 at 10:19
Mauro ALLEGRANZAMauro ALLEGRANZA
11.6k11939
answered Dec 29 '18 at 10:19
Mauro ALLEGRANZAMauro ALLEGRANZA
11.6k11939
answered Dec 29 '18 at 10:19
Mauro ALLEGRANZAMauro ALLEGRANZA
11.6k11939
11.6k11939
add a comment |
add a comment |
Thanks for contributing an answer to History of Science and Mathematics Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fhsm.stackexchange.com%2fquestions%2f8109%2fwhy-are-x-and-y-commonly-used-as-mathematical-placeholders%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
1
$begingroup$
May I ask why this is off-topic or unclear?
$endgroup$
– Sweet_Cherry
Dec 30 '18 at 18:14
$begingroup$
I was somewhat put off by the migration from ELU to here, but the word mathematical was finally added. However, after looking up placeholder it seems to only have two general definitions. It has the obvious math one that we all know. But there's also some (academic?) linguistic definition that I don't quite understand. Regardless, what I cannot find is what I thought it meant, which is what one might assume place holder means. IMO: a stand-in (which is about people; n/a) - tl;dr: I can't find a definition of placeholder in reference to a physical object, which is surprising.
$endgroup$
– Mazura
Dec 30 '18 at 23:23
$begingroup$
@Mazura Originally I posted it on ELU because most people were using X and Y in their questions. I was aware that it was used in math (obviously), but I wasn't aware of this S.E. By placeholder, I mean an unknown number/word.
$endgroup$
– Sweet_Cherry
Dec 30 '18 at 23:26
$begingroup$
With the addition of mathematical I don't see how it could be anymore on-topic or anymore clear. And unfortunately, any less the question that I actually wanted answered: When was X first used as a substitute for a given object or person, with an unknown quantity or quality?
$endgroup$
– Mazura
Dec 30 '18 at 23:28
1
$begingroup$
Because a and b are busy being a) used elsewhere and b) to denote alternatives
$endgroup$
– Valorum
Dec 31 '18 at 10:27