Simpliest possible linear wave equation?

[ojek]

Homework Statement

Hello, as in topic, i am looking for simpliest wave equation i can get, i don't really need to know what it is etc., i only need it to be as simple as possible.

Homework Equations

The Attempt at a Solution

I think that simpliest wave equation will be just y = x*x, am i correct?

 

[ojek]

Help please?

 

[ojek]

Anyone?