Deriving the Wave Equation from Laplacian and Partial Derivatives

[nmsurobert]

Homework Statement

derive the following wave equation
∇²H = 1/c² (∂²H/∂t²)

Homework Equations

The Attempt at a Solution

I'm not sure how to derive it. I suppose I can break it into a whole bunch of partial derivatives because of the del squared operator and then just lump the three partial derivatives (Hx, Hy, Hz) back into H but I don't know if that's a derivation of the equation.

 

[BvU]

Derive from what ? Your relevant equations are missing, the problem statement is almost missing (we have no idea what H stands for). Have some compassion with helpers of good will !