Problem $1$:

The function $y$ is defined as

$y=\{\begin{array}{cc}0,& x<mn\; id="EditorElement\_5448412">0</mn>\\ e^x(x+1),& 0x<mn\; id="EditorElement\_5448449">1</mn>\\ \frac{e^{-x}}{x+1},& x1\end{array}$

Using a for loop or otherwise,

$($a$)$ Determine the $y$ values in a vector called $z$ for $x$ values from $0$ to $4$ in steps of $0\mathrm{.}4.$ Display

the values of vector $z.$

$($b$)$ Determine and display the sum of values of the vector $z.$