b=2.718281828;x=1:1:1000;n=length(x);
a=75;
for i=1:n

y(i)=(1/(a*sqrt(pi)))*(a/x(i))^1.5*exp(-a/x(i));
end
plot(x,y)
%sum(y)=.9252 pentru n=17000 si.8836 pentru n=7000 ;
%n=1000 da sum(y)=.6986