Kirchhoff formula
= Kirchhoff formula
{c}
In three spatial dimensions, the solution with initial position $u_0$ and velocity $u_1$ is
$$
u(t,x)=\partial_t\bigl(tM_tu_0(x)\bigr)+tM_tu_1(x),
$$
where $M_t$ is the spherical mean.
= Kirchhoff formula
{c}
In three spatial dimensions, the solution with initial position $u_0$ and velocity $u_1$ is
$$
u(t,x)=\partial_t\bigl(tM_tu_0(x)\bigr)+tM_tu_1(x),
$$
where $M_t$ is the spherical mean.