Write a MATLAB script to generate and plot the following functions on the interval $5<=$x$<=5$:

$1.$ y$=$e$^(-$x$^2)$

$2.$ y$=1/(1+$e$^(-$x$))$

$3.$ y$=1/(1+$e$^$x$)$

Plot these functions using different line styles and colors, label the axes appropriately, provide a title for the graph, and include a legend to distinguish between the curves.