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Thank you for your suggestion. I tried to run but again it took time and I guess Mathematica would not give answer.
Thank you for your great help! :)
Dear Marco, Thank you very much for your advice. I have followed them and I still have few to ask. If I get `k[y]` from this, p = 1.57516; a1 = 1.7824; \[Alpha] = 1/2 Pi; f[k_?NumericQ] := p*NIntegrate[ ...
Hi Henrik! Thank you very much for your response and sharing your code! Mathematica is great and so are you :)