function atimesv(a,v)
% atimesv displays a two-dimensional
% plot of the scalar-vector product a*v,
% where a is a real scalar and v is a two
% dimensional real vector.
%
% This function displays a plot of a*v
% following the illustration of Figure 1.1 in G. Strang,
% "Introduction to Linear Algebra."
% Written by T. A. Bryan on 2 June 1993
x=a*v;
hold off
clg
plot([0 v(1)],[0,v(2)],':',...
[0 x(1)],[0,x(2)],'-')
hold on
text(v(1),v(2),'v')
text(x(1),x(2),[num2str(a) '*v'])
hold off