Solving a PDE for z(x,y) with Total and 2nd Derivatives: Step-by-Step Guide

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In summary, the conversation discusses a function Z(x,y) that is affected by the functions x and y, where y is a function of x. It is mentioned that y'(x) represents the total derivative of y with respect to x, and y"(x) is the 2nd derivative. The conversation also mentions the use of separation of variables as a strategy to solve the problem, and provides resources for further understanding. It is mentioned that the solution to the PDE is Z(x,y), and that the first two parts resemble a wave equation.
  • #1
chacal10
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I have not been able to solve this PDE; need some help pls
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as you can see, z(x,y) is a function of x, y; and y is a function of x, therefore y'(x) is the total derivative of "y" respect to "x", and y"(x) is the 2nd derivative. y'(x)^2 is just the square of the derivative of y respect to x

I don't have boundary or initial conditions, so you can make up any if that simplifies finding the solution

Thank you !
 
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  • #2
Have you tried the separation of variables strategy?

Assume ##Z(x,y) = X(x)Y(y)##
 
  • #4
Let me try that. I think the problem with separation of variables is the total derivative terms y'(x) and y"(x) that multiply the partial derivatives
 
  • #5
I don't know much about PDEs but I see you're looking for two functions here, shouldn't there be a system of coupled equations instead of just one?
 
  • #6
@TheDS1337
Is actually one function Z(x,y), but "y" itself is a function of "x" (unknown at this time)
What I am trying to find as the "solution" to this PDE is Z(x,y), i.e. something like "...Z(x,y) = A*cos(y-wx) + exp(-y*x)..." or something like that.
Note that the first 2 parts of the PDE look suspiciously close to a wave equation (if you replace "x" by "t"), but then the 3rd part messes the whole thing up

Thank you all!
 

Related to Solving a PDE for z(x,y) with Total and 2nd Derivatives: Step-by-Step Guide

1. What is a PDE and why is it important to solve it?

A PDE (partial differential equation) is a mathematical equation that involves partial derivatives of an unknown function of two or more independent variables. It is important to solve PDEs because they are used to describe many physical phenomena in science and engineering, such as heat transfer, fluid mechanics, and quantum mechanics.

2. What are total and 2nd derivatives and how are they used in solving a PDE for z(x,y)?

Total derivatives are used to describe the change in a function with respect to all of its independent variables. Second derivatives are used to describe the rate of change of a function's slope. In solving a PDE for z(x,y), total and 2nd derivatives are used to find the partial derivatives of z with respect to x and y, which are then used to construct the PDE.

3. What are the steps involved in solving a PDE for z(x,y) with total and 2nd derivatives?

The steps involved in solving a PDE for z(x,y) with total and 2nd derivatives include identifying the type of PDE, finding the total derivatives of z with respect to x and y, substituting these derivatives into the PDE, simplifying the resulting equation, and then solving for z(x,y).

4. Can you provide an example of solving a PDE for z(x,y) with total and 2nd derivatives?

Yes, an example of solving a PDE for z(x,y) with total and 2nd derivatives is the heat equation: ∂z/∂t = k (∂²z/∂x² + ∂²z/∂y²), where z represents temperature, t represents time, and k is a constant. By finding the total derivatives of z with respect to x and y, substituting them into the PDE, and solving for z(x,y), we can determine the temperature distribution over time in a given system.

5. Are there any limitations to solving a PDE for z(x,y) with total and 2nd derivatives?

Yes, there are some limitations to solving a PDE for z(x,y) with total and 2nd derivatives. These include the complexity of the PDE, the availability of analytical solutions, and the accuracy of numerical methods used to solve the PDE. Additionally, certain boundary conditions must be known in order to obtain a unique solution.

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