1. The problem statement, all variables and given/known data I must use the wave equation to to find the speed of a wave. y(x,t) = (3.0mm) sin [(4.00mm^-1)x - (7.00 s^-1)t] 2. Relevant equations Here's the wave equation. It has strange symbols. (∂^2 y) / (∂ x^2) = (1 / v^2) ((∂^2 y)/ (∂^2 t) 3. The attempt at a solution There's no way that I can attempt this solution if I don't know how to use this formula. Do I just take the derivative.