Solve the problem
PDE: $\quad u_t = u_{xx} , \qquad -\infty < x < \infty , \quad t > 0$
IC: $\quad u(x,0) = 3 \delta(x) + 6 \delta(x-8)$
where $\delta$ is the delta function (impulse).

$\displaystyle u(x,t) = {}$

help (formulas)