(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

my non linear pde is

du/dt = d/dx [3u^{2}- d^{2}u/dx^{2}]

The question says to let u(x,t) = f(x-ct)

Where the function f tends to 0, f' tends to 0 and f'' tends to 0 but the (x-ct) tends to positive or negative infinity.

2. Relevant equations

i thought the solution was to find du/dt du/dx d^{2}u/dt^{2}and d^{2}u/dx^{2}

Which gave me in order as above, -cf' , f' , c^{2}f'' , f''

3. The attempt at a solution

But when i substitute these into the pde i get -cf' = d/dx[3f^{2}- f"] which im not sure actually helps

Could someone please tell me if i am using the correct method or if i have done it completely wrong

Thank you

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Non linear pde need to change it to an ode

Can you offer guidance or do you also need help?

**Physics Forums | Science Articles, Homework Help, Discussion**