A semi$-$infinite plate is

similar to that in Fig. $13\mathrm{.}5-2.$ At the surfaces x $=0$ and x $=$ L$,$ the

temperature is held constant at $200$ K$.$ At the surface y $=0,$ the

temperature is held at $400$ K$.$ If L $=1\mathrm{.}0$ m$,$ calculate the temperature

at the point y $=0\mathrm{.}5$ m and x $=0\mathrm{.}5$ m at steady state.