D$\mathrm{.}4($a$)$ Write a function called unitstep that takes a single real argument t and returns u$($t$),$ where

u$($t$)=($

$1$ t $>=0$

$0$ otherwise.

$($b$)$ Modify the function from part $($a$)$ so that it takes a single vector argument t $=[$t$1$ t$2...$ tn $]$

T

$($where n $>=1$ and

t$1,$t$2,...,$tn are real$)$ and returns the vector $[$ u$($t$1)$ u$($t$2)...$ u$($tn$)]$

T

$.$ Your solution must employ a looping construct

$($e$.$g$.,$ a for loop$).$

$($c$)$ With some ingenuity, part $($b$)$ of this exercise can be solved using only two lines of code, without the need

for any looping construct. Find such a solution. $[$Hint: In MATLAB, to what value does an expression like

$[-2-1012]>=0$ evaluate?$]$