x = -10:0.01:10;
y4 = tpdf(x,3);
y2 = tpdf(x,1);
y11 = tpdf(x,10);
y21 = tpdf(x,20);

figure
plot(x,y2,x,y4,x,y11,x,y21)
hold on
plot(x,normpdf(x,0,1),'k--','Linewidth',1.5)

legend('T1 pdf','T3 pdf','T10 pdf','T20 pdf','Normal(0,1) pdf')

figure
semilogy(x,y2,x,y4,x,y11,x,y21)
hold on
semilogy(x,normpdf(x,0,1),'k--','Linewidth',1.5)

legend('T1 pdf','T3 pdf','T10 pdf','T20 pdf','Normal(0,1) pdf','Location','best')
[-10 10 1e-10 1]
