$($a$)$ Create a variable a that is a row vector with the following elements: ${3\mathrm{.}9}^3,7sin65,\frac{4\mathrm{.}2x{10}^3}{e^5},20\mathrm{.}5,\frac{32}{6-{3\mathrm{.}2}^2},$ and $\sqrt[\phantom{2}]{61}(tan\frac{}{5}+0\mathrm{.}28)$