A plane wall with linearly increasing area has surface temperatures $T_{s,1}$ and $T_{s,2},$ where $T_{s,1}>T_{s,2,},$ Under

$1$D$,$ steady state conditions, and no heat generation, sketch $($i$)$ the heat flow along the wall; $($ii$)$ the heat flux

along the wall; and $($iii$)$ the temperature distribution along the wall when $k(x)$ is $($a$)$ constant; $($b$)$ increasing

with $x$; and $($c$)$ decreasing with $x.$