The similarity solution for the diffusion equation, $\frac{\text{d}\text{e}\text{l}\text{u}}{\text{d}\text{e}\text{l}\text{t}}=\frac{de{l}^{2}u}{del{x}^2}$ is $u(x,t)=u().$ Where similarity variable, $=\frac{x}{\sqrt[\phantom{2}]{t}}.$ If $u(x,0)=e^{-x^2}.$ the ratio $\frac{u(0,1)}{u(0,4)}=($round off to one decimal place$)$