$3-23$ A $1\mathrm{.}0m1\mathrm{.}5m$ double$-$pane window consists of two $4-$mm$-$thick layers of glass $(k=0\mathrm{.}78\frac{W}{m}*K$ that are separated by a $5-mm$ air gap $(($:$k_{\text{a}\text{i}\text{r}}=0\mathrm{.}025\frac{W}{m}*K\}.$ The heat flow through the air gap is assumed to be by conduction. The inside and outside air temperatures are $20C$ and $-20C,$ respectively, and the inside and outside heat transfer coefficients are $40$ and $20\frac{W}{m^2}*K.$ Determine $($a$)$ the daily rate of heat loss through the window in steady operation and $(b)$ the temperature difference across the largest thermal resistence.