$...$something... $=$ fzero$(...$Thrust...$)$

$($c$)$ Your final answer for the optimal thrust, kN $,$ rounded to four decimals $($not $4$ sig. figs; I do mean

$4$ decimals, like $20\mathrm{.}3941$ kN $).$

SAVE the function Thrust. m you wrote $-$ you'll need it again for the MATLAB problem $3\mathrm{.}5$