# Taking foureir integral in polar coordinate

hi;

I have a question about taking the foureir trasnform in polar coordinate... the quesiton is as following;
https://www.physicsforums.com/attachment.php?attachmentid=17892&stc=1&d=1236524155

I would like to learn that according to outermost integral ($$\rho$$), the integral is taken. But here I would like to now how it is happened step by step... because in the second equation we have 2/$$\lambda$$ and exp(-j4pi 1/$$\lambda$$) and G($$\theta$$)... How were they put in the equation???...

if you can explain it, I will be really glad...