Difference between a differential, dx, and the change in a variable, delta x?

In summary, the difference between a differential, dx, and the change in a variable, delta x, is that dx is the infinitesimally small change in a variable with respect to a function, while delta x is the change in the domain. When taking a derivative, dx represents the change in x while delta x represents the change in the domain. This is demonstrated on a position-time graph where delta x divided by delta t gives the average velocity, while dx/dt gives the instantaneous velocity.
  • #1
erraticimpulse
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What's the difference between a differential, dx, and the change in a variable, delta x? Is dx the change in a variable with respect to a function while delta x is the change in the domain?
 
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  • #2
Delta x is like what you say, the change in x... or ... Xfinal-Xinitial. When you take a derivative with respect to x (dx being the differential) you are taking the change in x (delta x) to be infinitly small.

So on a position-time graph when you find delta x and divide it by delta t, you find the average velocity. However, if you take the derivative of the position function with respect to time (dx/dt), you still have the same units as before, but you have found the instantaneous velocity.

I hope this helps!
 
  • #3


The difference between a differential, dx, and the change in a variable, delta x, lies in their definitions and usage in mathematics.

A differential, also known as a differential element, is an infinitesimal change in a variable, typically denoted as dx. It is used in calculus to represent the change in a function as its input variable changes. For example, in the function f(x), dx represents the change in x that results in a corresponding change in f(x). Differentials are often used in differential equations and integration.

On the other hand, delta x represents the change in a variable in a specific interval, usually denoted as Δx. It is used to measure the difference between the initial and final values of a variable. For instance, if x1 and x2 are the initial and final values of a variable x, then Δx = x2 - x1. Delta x is commonly used in algebra and geometry to calculate slope, distance, and other quantities that involve a change in a variable.

In summary, dx is an infinitesimal change in a variable with respect to a function, while delta x is a finite change in a variable in a specific interval. In other words, dx represents a small change in a variable, while delta x represents a larger change in the same variable. Additionally, dx is often used in calculus, while delta x is used in various areas of mathematics, such as algebra and geometry.
 

Related to Difference between a differential, dx, and the change in a variable, delta x?

1. What is the difference between a differential and dx?

A differential is an infinitesimal change in a variable, while dx is a notation used to represent a differential in calculus. In other words, dx is a shorthand way of writing "a small change in x".

2. How is a differential different from the change in a variable, delta x?

A differential is a theoretical concept that represents an infinitely small change in a variable, while delta x is a finite change in a variable. In other words, delta x is a measurable quantity while a differential is not.

3. Can you give an example of a differential and delta x?

An example of a differential is the derivative of a function, which is represented by dy/dx. An example of delta x is the difference between two points on a graph, such as the change in x values from (3,5) to (6,8).

4. Why is understanding the difference between a differential and dx important in calculus?

Understanding the difference between a differential and dx is important in calculus because it helps us to accurately calculate derivatives and integrals. Differentials allow us to work with infinitesimal changes, which is essential in many mathematical models.

5. How do differentials and delta x relate to the concept of limits?

Differentials and delta x are closely related to the concept of limits. In calculus, we use differentials and delta x to define the derivative, which is the slope of a curve at a specific point. This is done by taking the limit of delta x approaching zero, or in other words, as the change in x becomes infinitesimally small.

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