Wave equation

The wave equation in one dimension is:

v^-2∂²H/∂t² - ∂²H/∂x² = 0

two dimensions:

v^-2∂²H/∂t² - (∂²H/∂x² + ∂²H/∂y²) = 0

three dimensions:

v^-2∂²H/∂t² - ∇²H = 0

where v is the term that describes the velocity of the wave, and H is the quantity that the wave is propogating through. Note that H can be either a vector (like the electric and magnetic fields) or a scalar (like density or pressure).