Q$1$function h $=$ manning$\_$equation$\_$secant$($Q$,$ s$,$ b$,$ n$,$ h$1,$ h$2,$ epsilon$\_$s$)$ f $=$ @$($h$)$ Q $-($sqrt$($s$)*($b $*$ h$)^(5/3))/($n $*($b $+2*$ h$)^(2/3))$; while abs$($h$2-$ h$1)>$ epsilon$\_$s h $=$ h$2-$ f$($h$2)*($h$2-$ h$1)/($f$($h$2)-$ f$($h$1))$; h$1=$ h$2$; h$2=$ h; endendQ $=5$;s $=0\mathrm{.}0002$;b $=20$;n $=0\mathrm{.}03$;h$1=0$;h$2=2$;epsilon$\_$s $=0\mathrm{.}001$;h $=$ manning$\_$equation$\_$secant$($Q$,$ s$,$ b$,$ n$,$ h$1,$ h$2,$ epsilon$\_$s$)$;h$\_$values $=$ linspace$(0,1,100)$;Q$\_$values $=($sqrt$($s$)*($b $*$ h$\_$values$).^(5/3))./($n $*($b $+2*$ h$\_$values$).^(2/3))$;figure;plot$($h$\_$values, Q$\_$values, 'LineWidth', $2)$;xlabel$(\text{'}$Depth $($h$)\text{'})$;ylabel$(\text{'}$Flow $($Q$)\text{'})$;title$(\text{'}$Manning Equation'$)$;grid on;