I have been using Mathematica 9 to solve a double integration (Equation 1) but without any success. 
I was told that the value of $\alpha$ will be 0.2826 when the following data is used for the constants: 
I uses NIntegrate but still can't obtain 0.2828 for the $\alpha$ value. I am not sure if i have the code wrong and hope someone in the community can help.
