How to notate a variable that is being held constant

In summary: For example, ##y=f(x)##.In summary, the conversation discusses a symbol or notation used to indicate a variable being held constant in equations, particularly in math and physics. Some suggestions for this notation include using a dollar sign around the variable or using function notation to explicitly denote the variable. However, there is no standard notation for this concept and it may be best to explain it through clear communication rather than relying on a specific symbol.
  • #1
jldibble
50
0
I remember learning at one point that you can put some sort of symbol on top or near a variable to indicate that it is being held constant. I thought that it was just a bar drawn above the variable but in some cases, it means "the average of."

Anyone know what I'm talking about?
 
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  • #2
jldibble said:
I remember learning at one point that you can put some sort of symbol on top or near a variable to indicate that it is being held constant. I thought that it was just a bar drawn above the variable but in some cases, it means "the average of."

Anyone know what I'm talking about?

Do you mean that, when taking a partial derivative and want to specifically keep t constant, you can write, for example, ##\left(\frac{\partial f}{\partial x}\right)_t##?
 
  • #3
Mandelbroth said:
Do you mean that, when taking a partial derivative and want to specifically keep t constant, you can write, for example, ##\left(\frac{\partial f}{\partial x}\right)_t##?

No, I mean something much simpler. It's a symbol or notation that you'd use as you're explaining how variables will change relative to each other.

Here's a very simple example using the equation d=vt (distance = speed*time):

Say I want to hold the speed at a constant value; I now know that by increasing the amount of time, I'll increase the value of the distance by a proportionate amount. My question involves a short-hand symbol for indicating that the speed is the variable that's being held constant, instead of wasting time writing out "___ is constant" everytime I'm discussing an equation.
 
  • #4
In spreadsheet programs like excel this is done by putting '$' '$' around the variable, though I doubt that's what you're looking for.

Do you mean just saying:
##D= \frac{v}{t} \rightarrow D= \frac{v_1}{t}##? Because that sort of does it.
 
  • #5
Vorde said:
Do you mean just saying:
##D= \frac{v}{t} \rightarrow D= \frac{v_1}{t}##? Because that sort of does it.


That's more like it, but not exactly what I had in mind.

It's such a dumb little thing but it's driving me nuts.

Thanks for the reply
 
  • #6
jldibble said:
That's more like it, but not exactly what I had in mind.

It's such a dumb little thing but it's driving me nuts.

Thanks for the reply

What class was it? That might help?
 
  • #8
Vorde said:
What class was it? That might help?

It's not for a specific class. I tutor for math and physics and there are times when I want to denote which variable in the equation is being held constant for the sake of discussing how the other variables effect each other.

I remember a math (or science) teacher I had in high school making a mark near the variable that would be held constant.
 
  • #9
jldibble said:
It's not for a specific class. I tutor for math and physics and there are times when I want to denote which variable in the equation is being held constant for the sake of discussing how the other variables effect each other.

I remember a math (or science) teacher I had in high school making a mark near the variable that would be held constant.

I'm not familiar with any standard notation that denotes what you want. You could make one up for the students you are tutoring, but let them know it's not a notation they're likely to see elsewhere.

You could say something like "let d = x(t) = vt", where the function notation x(t) explicitly denotes that t is the variable. If the students need a mark to remind them which symbols are constants, function notation may at first be confusing for them, but it's a notation they will likely see again in the future.
 
  • #10
If you are talking about the distinction between "dependent variables" and "independent variables", I am not familiar with any specific notation, but there is a common convention of formulating equations so that the dependent variable goes on the left and the independent variable or variables go on the right.
 
Last edited:

1. What does it mean to hold a variable constant?

Holding a variable constant means that its value is not allowed to change in the given context or scenario. It remains the same throughout the experiment or study.

2. Why is it important to notate a variable that is being held constant?

Notating a variable that is being held constant is important because it allows for clear communication and understanding of the experiment or study. It also helps ensure that the results are accurate and reliable.

3. How do you notate a variable that is being held constant?

The most common way to notate a variable that is being held constant is by using the symbol "c" or "const" next to the variable symbol. For example, if the variable is time, it can be notated as "t const".

4. Can a variable be held constant in all situations?

No, a variable can only be held constant if it is possible and relevant to the experiment or study. In some cases, it may not be possible to hold a variable constant, or it may not be necessary to do so.

5. What is the purpose of holding a variable constant in an experiment or study?

The purpose of holding a variable constant is to isolate the effect of other variables on the outcome of the experiment or study. By keeping one variable constant, the researcher can determine the specific impact of the other variables being tested.

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