Subtleties of “unknown” vs. “variable” The 2019 Stack Overflow Developer Survey Results Are In Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern)Logic in the use of variablesWhat is a relatively bound variable?Find groups of threeHigh school math definition of a variable: the first step from the concrete into the abstract…How to determine the operation(s) needed to obtain same value for variable in two formulas?What's the difference between an independent and dependent variable?Difference between variables, parameters and constantsReducing two variables at a timeWhat is the meaning of the phrase “localizing the value of a function”?How can I derive k or x in s = (m + r*x)/k, when x is unknown constant and k is unknown variable?What’s the difference between “the value x” and “the value of x”?
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Subtleties of “unknown” vs. “variable”
The 2019 Stack Overflow Developer Survey Results Are In
Announcing the arrival of Valued Associate #679: Cesar Manara
Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern)Logic in the use of variablesWhat is a relatively bound variable?Find groups of threeHigh school math definition of a variable: the first step from the concrete into the abstract…How to determine the operation(s) needed to obtain same value for variable in two formulas?What's the difference between an independent and dependent variable?Difference between variables, parameters and constantsReducing two variables at a timeWhat is the meaning of the phrase “localizing the value of a function”?How can I derive k or x in s = (m + r*x)/k, when x is unknown constant and k is unknown variable?What’s the difference between “the value x” and “the value of x”?
$begingroup$
I'm trying to pin down the difference between "unknown" and "variable". I have always understood that in the equations $2x+1=10$ or $x^2+5x+6=0$, $x$ is an unknown (short for "unknown constant"), since its value can be determined. In the expression $2x+1$, however, $x$ can take any value, therefore it is a variable.
What about in the equation $2x+3y=10$? $x$ and $y$ can both take infinitely many values, but once one is fixed, the other becomes fixed. Does this mean they are both variables? Does it mean that one (say $x$) is a variable, but the other is an unknown (since its value is determined by the variable)?
I'd appreciate some insight. Thanks.
algebra-precalculus terminology
edited Oct 16 '17 at 12:06
zoli
17.1k41945
asked Oct 16 '17 at 11:54
Trying to get betterTrying to get better
263
$endgroup$
add a comment |
$begingroup$
I'm trying to pin down the difference between "unknown" and "variable". I have always understood that in the equations $2x+1=10$ or $x^2+5x+6=0$, $x$ is an unknown (short for "unknown constant"), since its value can be determined. In the expression $2x+1$, however, $x$ can take any value, therefore it is a variable.
What about in the equation $2x+3y=10$? $x$ and $y$ can both take infinitely many values, but once one is fixed, the other becomes fixed. Does this mean they are both variables? Does it mean that one (say $x$) is a variable, but the other is an unknown (since its value is determined by the variable)?
I'd appreciate some insight. Thanks.
algebra-precalculus terminology
edited Oct 16 '17 at 12:06
zoli
17.1k41945
asked Oct 16 '17 at 11:54
Trying to get betterTrying to get better
263
$endgroup$
2
$begingroup$
"unknown" and "variable" are no formal terms. They are mostly used interchangeably. Which one is more appropriate can often be seen not only from the formula, but a problem statement is necessary. So saying this, $x$ and $y$ in $2x+3y=10$ can be considered both, as long as you do not state where this formula comes from or what you are using it for.
$endgroup$
– M. Winter
Oct 16 '17 at 12:09
$begingroup$
Regarding "variable", see the post: logic-in-the-use-of-variables.
$endgroup$
– Mauro ALLEGRANZA
Oct 16 '17 at 12:32
$begingroup$
See Equation: "In mathematics, an equation is a statement of an equality containing one or more variables. Solving the equation consists of determining which values of the variables make the equality true. Variables are also called unknowns and the values of the unknowns which satisfy the equality are called solutions of the equation."
$endgroup$
– Mauro ALLEGRANZA
Oct 16 '17 at 12:41
add a comment |
$begingroup$
I'm trying to pin down the difference between "unknown" and "variable". I have always understood that in the equations $2x+1=10$ or $x^2+5x+6=0$, $x$ is an unknown (short for "unknown constant"), since its value can be determined. In the expression $2x+1$, however, $x$ can take any value, therefore it is a variable.
What about in the equation $2x+3y=10$? $x$ and $y$ can both take infinitely many values, but once one is fixed, the other becomes fixed. Does this mean they are both variables? Does it mean that one (say $x$) is a variable, but the other is an unknown (since its value is determined by the variable)?
I'd appreciate some insight. Thanks.
algebra-precalculus terminology
edited Oct 16 '17 at 12:06
zoli
17.1k41945
asked Oct 16 '17 at 11:54
Trying to get betterTrying to get better
263
$endgroup$
I'm trying to pin down the difference between "unknown" and "variable". I have always understood that in the equations $2x+1=10$ or $x^2+5x+6=0$, $x$ is an unknown (short for "unknown constant"), since its value can be determined. In the expression $2x+1$, however, $x$ can take any value, therefore it is a variable.
What about in the equation $2x+3y=10$? $x$ and $y$ can both take infinitely many values, but once one is fixed, the other becomes fixed. Does this mean they are both variables? Does it mean that one (say $x$) is a variable, but the other is an unknown (since its value is determined by the variable)?
I'd appreciate some insight. Thanks.
algebra-precalculus terminology
algebra-precalculus terminology
edited Oct 16 '17 at 12:06
zoli
17.1k41945
asked Oct 16 '17 at 11:54
Trying to get betterTrying to get better
263
edited Oct 16 '17 at 12:06
zoli
17.1k41945
asked Oct 16 '17 at 11:54
Trying to get betterTrying to get better
263
edited Oct 16 '17 at 12:06
zoli
17.1k41945
edited Oct 16 '17 at 12:06
zoli
17.1k41945
edited Oct 16 '17 at 12:06
zoli
17.1k41945
17.1k41945
asked Oct 16 '17 at 11:54
Trying to get betterTrying to get better
263
asked Oct 16 '17 at 11:54
Trying to get betterTrying to get better
263
asked Oct 16 '17 at 11:54
Trying to get betterTrying to get better
263
263
2
$begingroup$
"unknown" and "variable" are no formal terms. They are mostly used interchangeably. Which one is more appropriate can often be seen not only from the formula, but a problem statement is necessary. So saying this, $x$ and $y$ in $2x+3y=10$ can be considered both, as long as you do not state where this formula comes from or what you are using it for.
$endgroup$
– M. Winter
Oct 16 '17 at 12:09
$begingroup$
Regarding "variable", see the post: logic-in-the-use-of-variables.
$endgroup$
– Mauro ALLEGRANZA
Oct 16 '17 at 12:32
$begingroup$
See Equation: "In mathematics, an equation is a statement of an equality containing one or more variables. Solving the equation consists of determining which values of the variables make the equality true. Variables are also called unknowns and the values of the unknowns which satisfy the equality are called solutions of the equation."
$endgroup$
– Mauro ALLEGRANZA
Oct 16 '17 at 12:41
add a comment |
2
$begingroup$
"unknown" and "variable" are no formal terms. They are mostly used interchangeably. Which one is more appropriate can often be seen not only from the formula, but a problem statement is necessary. So saying this, $x$ and $y$ in $2x+3y=10$ can be considered both, as long as you do not state where this formula comes from or what you are using it for.
$endgroup$
– M. Winter
Oct 16 '17 at 12:09
$begingroup$
Regarding "variable", see the post: logic-in-the-use-of-variables.
$endgroup$
– Mauro ALLEGRANZA
Oct 16 '17 at 12:32
$begingroup$
See Equation: "In mathematics, an equation is a statement of an equality containing one or more variables. Solving the equation consists of determining which values of the variables make the equality true. Variables are also called unknowns and the values of the unknowns which satisfy the equality are called solutions of the equation."
$endgroup$
– Mauro ALLEGRANZA
Oct 16 '17 at 12:41
2
2
$begingroup$
"unknown" and "variable" are no formal terms. They are mostly used interchangeably. Which one is more appropriate can often be seen not only from the formula, but a problem statement is necessary. So saying this, $x$ and $y$ in $2x+3y=10$ can be considered both, as long as you do not state where this formula comes from or what you are using it for.
$endgroup$
– M. Winter
Oct 16 '17 at 12:09
$begingroup$
"unknown" and "variable" are no formal terms. They are mostly used interchangeably. Which one is more appropriate can often be seen not only from the formula, but a problem statement is necessary. So saying this, $x$ and $y$ in $2x+3y=10$ can be considered both, as long as you do not state where this formula comes from or what you are using it for.
$endgroup$
– M. Winter
Oct 16 '17 at 12:09
$begingroup$
Regarding "variable", see the post: logic-in-the-use-of-variables.
$endgroup$
– Mauro ALLEGRANZA
Oct 16 '17 at 12:32
$begingroup$
Regarding "variable", see the post: logic-in-the-use-of-variables.
$endgroup$
– Mauro ALLEGRANZA
Oct 16 '17 at 12:32
$begingroup$
See Equation: "In mathematics, an equation is a statement of an equality containing one or more variables. Solving the equation consists of determining which values of the variables make the equality true. Variables are also called unknowns and the values of the unknowns which satisfy the equality are called solutions of the equation."
$endgroup$
– Mauro ALLEGRANZA
Oct 16 '17 at 12:41
$begingroup$
See Equation: "In mathematics, an equation is a statement of an equality containing one or more variables. Solving the equation consists of determining which values of the variables make the equality true. Variables are also called unknowns and the values of the unknowns which satisfy the equality are called solutions of the equation."
$endgroup$
– Mauro ALLEGRANZA
Oct 16 '17 at 12:41
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
It depends what your question is. While they are kind of interchangeable, these two terms are used in different contexts. Unknown is usually employed in equations,so for example you could ask how to solve the equation $2x=1$,where $x$ is the unknown. On the other hand the term variable is more used in case of functions. You could ask for example what is the second derivative according to the $x$ variable of the function $f(x,y)=x^2+y+2$. Hope that clears things up a bit.
edited Oct 16 '17 at 12:21
RGS
8,94311330
answered Oct 16 '17 at 12:19
KeenKeen
533110
$endgroup$
$begingroup$
Well, I'm happy with that difference already. It's the specific case of an equation with more than one variable/unknown where I think the distinction is unclear.
$endgroup$
– Trying to get better
Oct 19 '17 at 12:43
add a comment |
$begingroup$
I would say...a variable is an unknown but an unknown doesn't necessarily have to be a variable. A variable means it could be any number, it is not fixed but a unknown means it is a specific number that we do not know as yet. Therefore a variable is an unknown because it could be any number but an unknown doesn't have to be a variable because it is a fixed number that we do not know. Hope that makes sense.
answered Mar 24 at 16:08
D. SterlingD. Sterling
1
$endgroup$
$begingroup$
Can you try and be less vague?
$endgroup$
– egreg
Mar 24 at 16:12
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
It depends what your question is. While they are kind of interchangeable, these two terms are used in different contexts. Unknown is usually employed in equations,so for example you could ask how to solve the equation $2x=1$,where $x$ is the unknown. On the other hand the term variable is more used in case of functions. You could ask for example what is the second derivative according to the $x$ variable of the function $f(x,y)=x^2+y+2$. Hope that clears things up a bit.
edited Oct 16 '17 at 12:21
RGS
8,94311330
answered Oct 16 '17 at 12:19
KeenKeen
533110
$endgroup$
$begingroup$
Well, I'm happy with that difference already. It's the specific case of an equation with more than one variable/unknown where I think the distinction is unclear.
$endgroup$
– Trying to get better
Oct 19 '17 at 12:43
add a comment |
$begingroup$
It depends what your question is. While they are kind of interchangeable, these two terms are used in different contexts. Unknown is usually employed in equations,so for example you could ask how to solve the equation $2x=1$,where $x$ is the unknown. On the other hand the term variable is more used in case of functions. You could ask for example what is the second derivative according to the $x$ variable of the function $f(x,y)=x^2+y+2$. Hope that clears things up a bit.
edited Oct 16 '17 at 12:21
RGS
8,94311330
answered Oct 16 '17 at 12:19
KeenKeen
533110
$endgroup$
$begingroup$
Well, I'm happy with that difference already. It's the specific case of an equation with more than one variable/unknown where I think the distinction is unclear.
$endgroup$
– Trying to get better
Oct 19 '17 at 12:43
add a comment |
$begingroup$
It depends what your question is. While they are kind of interchangeable, these two terms are used in different contexts. Unknown is usually employed in equations,so for example you could ask how to solve the equation $2x=1$,where $x$ is the unknown. On the other hand the term variable is more used in case of functions. You could ask for example what is the second derivative according to the $x$ variable of the function $f(x,y)=x^2+y+2$. Hope that clears things up a bit.
edited Oct 16 '17 at 12:21
RGS
8,94311330
answered Oct 16 '17 at 12:19
KeenKeen
533110
$endgroup$
It depends what your question is. While they are kind of interchangeable, these two terms are used in different contexts. Unknown is usually employed in equations,so for example you could ask how to solve the equation $2x=1$,where $x$ is the unknown. On the other hand the term variable is more used in case of functions. You could ask for example what is the second derivative according to the $x$ variable of the function $f(x,y)=x^2+y+2$. Hope that clears things up a bit.
edited Oct 16 '17 at 12:21
RGS
8,94311330
answered Oct 16 '17 at 12:19
KeenKeen
533110
edited Oct 16 '17 at 12:21
RGS
8,94311330
edited Oct 16 '17 at 12:21
RGS
8,94311330
edited Oct 16 '17 at 12:21
RGS
8,94311330
8,94311330
answered Oct 16 '17 at 12:19
KeenKeen
533110
answered Oct 16 '17 at 12:19
KeenKeen
533110
answered Oct 16 '17 at 12:19
KeenKeen
533110
533110
$begingroup$
Well, I'm happy with that difference already. It's the specific case of an equation with more than one variable/unknown where I think the distinction is unclear.
$endgroup$
– Trying to get better
Oct 19 '17 at 12:43
add a comment |
$begingroup$
Well, I'm happy with that difference already. It's the specific case of an equation with more than one variable/unknown where I think the distinction is unclear.
$endgroup$
– Trying to get better
Oct 19 '17 at 12:43
$begingroup$
Well, I'm happy with that difference already. It's the specific case of an equation with more than one variable/unknown where I think the distinction is unclear.
$endgroup$
– Trying to get better
Oct 19 '17 at 12:43
$begingroup$
Well, I'm happy with that difference already. It's the specific case of an equation with more than one variable/unknown where I think the distinction is unclear.
$endgroup$
– Trying to get better
Oct 19 '17 at 12:43
add a comment |
$begingroup$
I would say...a variable is an unknown but an unknown doesn't necessarily have to be a variable. A variable means it could be any number, it is not fixed but a unknown means it is a specific number that we do not know as yet. Therefore a variable is an unknown because it could be any number but an unknown doesn't have to be a variable because it is a fixed number that we do not know. Hope that makes sense.
answered Mar 24 at 16:08
D. SterlingD. Sterling
1
$endgroup$
$begingroup$
Can you try and be less vague?
$endgroup$
– egreg
Mar 24 at 16:12
add a comment |
$begingroup$
I would say...a variable is an unknown but an unknown doesn't necessarily have to be a variable. A variable means it could be any number, it is not fixed but a unknown means it is a specific number that we do not know as yet. Therefore a variable is an unknown because it could be any number but an unknown doesn't have to be a variable because it is a fixed number that we do not know. Hope that makes sense.
answered Mar 24 at 16:08
D. SterlingD. Sterling
1
$endgroup$
$begingroup$
Can you try and be less vague?
$endgroup$
– egreg
Mar 24 at 16:12
add a comment |
$begingroup$
I would say...a variable is an unknown but an unknown doesn't necessarily have to be a variable. A variable means it could be any number, it is not fixed but a unknown means it is a specific number that we do not know as yet. Therefore a variable is an unknown because it could be any number but an unknown doesn't have to be a variable because it is a fixed number that we do not know. Hope that makes sense.
answered Mar 24 at 16:08
D. SterlingD. Sterling
1
$endgroup$
I would say...a variable is an unknown but an unknown doesn't necessarily have to be a variable. A variable means it could be any number, it is not fixed but a unknown means it is a specific number that we do not know as yet. Therefore a variable is an unknown because it could be any number but an unknown doesn't have to be a variable because it is a fixed number that we do not know. Hope that makes sense.
answered Mar 24 at 16:08
D. SterlingD. Sterling
1
answered Mar 24 at 16:08
D. SterlingD. Sterling
1
answered Mar 24 at 16:08
D. SterlingD. Sterling
1
answered Mar 24 at 16:08
D. SterlingD. Sterling
1
1
$begingroup$
Can you try and be less vague?
$endgroup$
– egreg
Mar 24 at 16:12
add a comment |
$begingroup$
Can you try and be less vague?
$endgroup$
– egreg
Mar 24 at 16:12
$begingroup$
Can you try and be less vague?
$endgroup$
– egreg
Mar 24 at 16:12
$begingroup$
Can you try and be less vague?
$endgroup$
– egreg
Mar 24 at 16:12
add a comment |
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$begingroup$
"unknown" and "variable" are no formal terms. They are mostly used interchangeably. Which one is more appropriate can often be seen not only from the formula, but a problem statement is necessary. So saying this, $x$ and $y$ in $2x+3y=10$ can be considered both, as long as you do not state where this formula comes from or what you are using it for.
$endgroup$
– M. Winter
Oct 16 '17 at 12:09
$begingroup$
Regarding "variable", see the post: logic-in-the-use-of-variables.
$endgroup$
– Mauro ALLEGRANZA
Oct 16 '17 at 12:32
$begingroup$
See Equation: "In mathematics, an equation is a statement of an equality containing one or more variables. Solving the equation consists of determining which values of the variables make the equality true. Variables are also called unknowns and the values of the unknowns which satisfy the equality are called solutions of the equation."
$endgroup$
– Mauro ALLEGRANZA
Oct 16 '17 at 12:41