Partial differential = the change?

In summary, the symbol "Δy/Δx" represents the change in y over the change in x, while the symbol "\partial y/\partial x" represents the partial derivative of y with respect to x. When the changes in y and x are small, the values of these two expressions will be approximately equal. However, if there are other independent variables involved, the partial derivative will be used to hold those variables at a fixed value while calculating the change in y with respect to x.
  • #1
rsaad
77
0
partial differential = the change??

Homework Statement



How is
Δy/Δx = [itex]\partial y[/itex] / [itex]\partial x[/itex] ?

I just don't know the logic behind this.
 
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  • #2


That is only approximately or asymptotically true. If Δy and Δx are small Δy/Δx will be near ∂y / ∂x.
 
  • #3


rsaad said:

Homework Statement



How is
Δy/Δx = [itex]\partial y[/itex] / [itex]\partial x[/itex] ?

I just don't know the logic behind this.
Do you understand how [itex]\Delta y/\Delta yx\approx dy/dx\ ?[/itex]

Usually, x & y are independent variables -- and often there are additional independent variables.

If f is a function of independent variables, x and y, then we write f(x,y).

[itex]\partial f/\partial x\ \ [/itex] is essentially [itex]\ \ df/dx\ \ [/itex] if we treat y as being held at some fixed value.

Then [itex]\ \ \Delta f/\Delta x \approx \partial f/\partial x\ \ [/itex] keeping y fixed at some value.



By the Way: If x & y are independent variables, then [itex]\ \ \partial y/\partial x=0 \ .[/itex]
 

Related to Partial differential = the change?

1. What is a partial differential?

A partial differential is a type of differential equation that involves multiple independent variables and their corresponding partial derivatives. It is used to model relationships between variables that are continuously changing.

2. How is a partial differential different from an ordinary differential?

An ordinary differential equation involves only one independent variable, while a partial differential equation involves multiple independent variables. Additionally, the derivatives in a partial differential equation are partial derivatives, which only consider the change in one variable while holding the others constant.

3. What types of problems can be solved using partial differentials?

Partial differential equations are commonly used in physics, engineering, and other fields to describe systems that involve continuous change, such as heat transfer, fluid flow, and wave motion. They can also be used in economics, biology, and other social sciences to model complex systems.

4. Can partial differentials be solved analytically?

In some cases, partial differential equations can be solved analytically using mathematical techniques such as separation of variables, Fourier series, or Laplace transforms. However, for more complex problems, numerical methods are often used to approximate the solution.

5. What are the applications of partial differentials in real life?

Partial differential equations have numerous applications in real life, including predicting weather patterns, designing aircraft and cars, simulating fluid flow in pipes and channels, and modeling the spread of diseases. They are also used in financial modeling and risk management.

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