I am integrating the following function between L and U using dblquad. I get "NaN" and a warning of singularity. F = real(constantForM.*((x-L).^(A(1)-1).*(y-L).^(A(2)-1).*(U-L-((x-L)+(y-L))).^(A(3)-1)).^2
where, constantForM = 3.378137617443966e-038. L = 1e-7 U = 3.2e5 A = [3.75 0.25 0.02]
In order to check for singularity, I generated 1e6 points between L and U and evaluated F at each of the points. I get a sharp peak(singularity) at halfway. But the value at that point is still less than 1. In fact the maximum value of F along these points is 0.00116 and minimum is close to zero. Then why do I get NaN??
Another thing: I used Monte Carlo Integration using the following method: 1. Evaluated F at all 1e6 points. 2. Found the average of all those values. 3. Multiplied by the volume i.e. (U-L)*(U-L). 4. I get 119 as the answer.