4. If u(x, t) satisfies the wave equation Utt = Uxx, prove the identity u(x + h, t + k) + u(x − h, t − k) = u(x + k, t + h) + u(x − k, t – h) for all x, t, h, and k. Sketch the quadrilateral Q whose vertices are the arguments in the identity.

Please help me with this question please thank you it's due today:(

Please help The first picture is the equation and the second is the question I need help on.

Hey, can you please answer question 22 and show you're work and how you did it in detail, so I can understand and give the answer, please.

I need help solving this, please explain or show your work so I can understand