$2\mathrm{.}21$ For the steel truss $)=(29{10}^6$ and loading shown, determine the deformations of members $AB$ and $AD,$ knowing that their crosssectional areas are $4\mathrm{.}0i{n}^2$ and $2\mathrm{.}8i{n}^2,$ respectively.

Fig. P$2\mathrm{.}21$