function r=betaplot(xmin,xmax,a,b,col)
%betaplot(xmin,xmax,a,b,col)
%plots a BETA distribution with parameters a and b > 0, in the interval [xmin,xmax]
%col is a text string which indicates the colour of the graph (default col='b')
%Copyright gianlucabaio2002

if nargin==4
   col='b';
end
if xmin<=0 | xmax<=0 |xmin>=1 |xmax>=1
   error('il supporto della variabile è [0,1]');
end

x=[xmin:.01:xmax];
const1=beta(a,b);
for i=1:length(x)
   y(i)=1/const1*x(i)^(a-1)*(1-x(i))^(b-1);
end

plot(x,y,col)