MATLAB: How to plot over histogram function

Question

I have the following code:

figure(2)
[h] = histogram(norm,100);
hold on
a=h.BinCounts;
b=h.BinEdges;
gaussiana = (1/(sqrt(2*pi)*desviacion))*exp(-0.5*(((b)/(desviacion)).^2));
laplaciana = (1/(sqrt(2)*desviacion))*exp(-(sqrt(2)*abs(b))/(desviacion));
gamma = (sqrt(sqrt(3)./(8.*pi.*desviacion.*abs(b)))).*exp(-(sqrt(3).*abs(b))./(2.*desviacion));
plot(b,gaussiana,'linewidth',2);
hold on
plot(b,laplaciana,'linewidth',2);
hold on
plot(b,gamma,'linewidth',2);

I am trying to plot over histogram but I cant make it work, I know that it is possible to do it using the old 'hist' function and then using 'bar', but I don't want to use that.

Answer 1

>> figure(2)
[h] = histogram(norm,100);
...
Error using norm
Not enough input arguments. 
>>

Your code even if fix the above doesn't normalize the histogram...try something like

hH=histogram(randn([100,1]),'Normalization','pdf');
hold on
x=linspace([-3,3]);
hL=line(x,normpdf(x));

which yielded for one particular trial