Question

Well, I’m trying to plot this graphic:

gnuplot> plot exp(-x) t 'MB' w l lw 3, (exp(x)-1)**(-1) w l lw 3 t 'BE', (exp(x)+1)**(-1) w l lw 3 t 'FD'

and exporting with

set terminal latex

How, or what, I have to do to the graphics be plotted in different lines styles, as dotted and dashed?

Answer 1

In order to specify line styles check the documentation here. You can specify the line type, line color, line width, point type etc.
To specify a blue dotted line on an X11 terminal do

set style line 1 lt 0 lc 3
plot x**2 ls 1

Note that the styles also depend on the terminal you are using. To see what possibilities there are use the test page of the current terminal by running test in your gnuplot console.

Examples of different line styles can be found here and there.