GNUPLOT is a free GNU package for plotting curves available for windows and Linux OS.
To start with one should install gnuplot package on his system depending upon support provided by OS.
in the console just type gnuplot prompt will change to : gnuplot>
now just write the desired command and feel the curve.
optionally one can also a package on LINUX kalgebra(fedora)
Syntax:
plot {[ranges]}
{[function] | {"[datafile]" {datafile-modifiers}}}
{axes [axes] } { [title-spec] } {with [style] }
{, {definitions,} [function] ...}