1. The problem statement, all variables and given/known data How can I find out if a function is a solution of a wave equation such as: (a) xt (b) log(xt) (c) x² + c²t² 3. The attempt at a solution Is it simply differentiating the funtion with respect to 'x' twice and equating this to the product of 1/c² and differentiating the function twice with respect to 't'? I tried doing it for part (c) and I got 1=1 which means its allowed I guess. As for part (a) I got 0=0 which i suppose it isn't?