Toronto Math Forum
APM3462019 => APM346Misc => Topic started by: MikeMorris on February 25, 2019, 07:24:53 PM

The solutions given to these questions make absolutely no sense to me. If the PDE is $u_{tt}  u_{xx} = 0$, how could the general solution possible be $u(x,t) = \phi(x+3t) + \psi(x3t)$? We have $c^{2} = 1$, so shouldn't it be $\phi(x+t) + \psi(xt)$? I am completely lost.

Misprints. Corrected