x=-3.5:0.001:3.5

hold on
y0=normpdf(x,0,1);
plot(x,y0)
axis([-3.5 3.5 0 0.5])

y2=tpdf(x,1);
plot(x,y2,'green')

y3=tpdf(x,5);
plot(x,y3,'red')

y4=tpdf(x,20);
plot(x,y4,'black')

y5=exp(x)./((ones(1,length(x))+exp(x)).^2);
plot(x,y5,'cyan')


legend('Normal','t(1)','t(5)','t(20)','Logistic',2);

hold off

