%This plots a simple quadratic
clear %clear memory
dx=1e-3; %Define the horizontal increment as 0.001.
x=-2:dx:2;  % The graph extends from -2 to +2.
y=3 * (x.^2) + 2 * x - 4;  %Define a parabola
xaxis = 0;
plot(x,y)   %Plot y and the x-axis.
axis([-2 2 -5 5])
grid
xlabel('x'); %Set plot labels
ylabel('y=3x^2+2x-4');
%axis([0 4*T*1e9 -5 10]) %Rescale y-axis