I'm fairly new to Fourier transformation. I know how to find the gaussian intergral of e^(-x^2). However this question has an addition ax term in the power of the exponential f(x)=Ae^(-x^-2+ax).
This was the given the solution. Please click on Fourier transformation to see image
But I still don't understand what happened from line 2 to line 3 and reading the explanation doesn't really help either. An explicit computation would be most appreciated!