Solving 2nd Order PDE for dx/ds in d^2x/ds^2 - (2/y)(dx/ds)(dy/ds) = 0

In summary, a 2nd order PDE (partial differential equation) is a mathematical equation involving two independent variables and their partial derivatives. To solve it, the equation must be classified as elliptic, parabolic, or hyperbolic and various techniques can be used, including numerical methods. The main difference between a 2nd order PDE and a 1st order PDE is the number of independent variables and their partial derivatives. Not all 2nd order PDEs can be solved analytically and they have many real-life applications, such as modeling heat and mass transfer, wave propagation, and fluid dynamics. They also have a role in quantum mechanics and general relativity.
  • #1
queequag
1
0

Homework Statement


Need to solve for dx/ds in the following equation, keeping dy/ds.


Homework Equations


d^2x/ds^2 - (2/y)(dx/ds)(dy/ds) = 0


The Attempt at a Solution



I can just rearrange to get:

dx/ds = (y/2)(ds/dy)(d^2x/ds^2)

But, this is not clean to use for some later calculations.

Is there any way to solve for dx/ds by integration?
 
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  • #2
Would it help you if I noticed that

[tex]\frac{d^2x}{ds^2} / \frac{dx}{ds} = \frac{d}{ds} \ln\left( \frac{dx}{ds} \right)[/tex]
?
 

Related to Solving 2nd Order PDE for dx/ds in d^2x/ds^2 - (2/y)(dx/ds)(dy/ds) = 0

1. What is a 2nd order PDE?

A 2nd order PDE (partial differential equation) is a mathematical equation that involves two independent variables and their partial derivatives. It is of the form: a(x,y)uxx + b(x,y)uxy + c(x,y)uyy = f(x,y,u,ux,uy), where u is the dependent variable and a, b, c are functions of x and y.

2. How do you solve a 2nd order PDE?

To solve a 2nd order PDE, you need to first classify it into one of the three categories: elliptic, parabolic, or hyperbolic. Then, you can use various techniques such as separation of variables, method of characteristics, or Fourier transforms to find the solution. In some cases, numerical methods may also be used.

3. What is the difference between a 2nd order PDE and a 1st order PDE?

A 2nd order PDE involves two independent variables and their partial derivatives, while a 1st order PDE involves only one independent variable and its partial derivative. This means that the solution to a 2nd order PDE is a function of two variables, while the solution to a 1st order PDE is a function of one variable.

4. Can all 2nd order PDEs be solved analytically?

No, not all 2nd order PDEs have analytical solutions. Some may require numerical methods to find an approximate solution. Additionally, the complexity of the equation and the boundary conditions also play a role in determining if an analytical solution is possible.

5. What are some real-life applications of 2nd order PDEs?

2nd order PDEs have many applications in physics, engineering, and other fields. They are commonly used to model heat and mass transfer, wave propagation, fluid dynamics, and diffusion processes. They also play a crucial role in quantum mechanics and general relativity.

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