Question $2$

Use the proof rules of Chapters $9$ and $10$ in $RB$ as well as selected portions in Chapter $3$ of Baber to derive preconditions for the following post conditions and program statements. Show all your working.

$2\mathrm{.}1,\{?\},i$:$=i+1$;$k$:$=k**2$;$j$:$=j-1,\{i=j\}$

$2\mathrm{.}2\{?\}$ while