Is There a Time Derivative for a Wave Equation?

The wave equation originates from well PDEs and like the, like how your wave equation is defined. That's just with the speed of light. And that's your light cone. Now we didn't talk about like time derivatives, initial derivatives. That's a little bit more complicated. But it's a cool kind of way to think about the wave equation because only those points between your right traveling wave of root and the left traveling rate root wave root can influence the value of your solution.