## anonymous 4 years ago Fourier transform question: My professor has been using this equation for the fourier transform:$F[f(\xi)]=\int\limits_{-\infty}^{\infty}f(x)e^{-i \xi x}dx$ But I have a book that claims this is the fourier transform: $F[f(\xi)]=\frac{1}{\sqrt{2 \pi}}\int\limits_{-\infty}^{\infty}f(x)e^{-i \xi x}dx$ So........ what's with the 1/sqrt(2 pi)? For context, this is a PDE class.

1. anonymous

I see a confusion about the fourier transform for angular and ordinary frequency http://en.wikipedia.org/wiki/Fourier_transform#Functional_relationships

2. ash2326

@abstracted both are correct, some books use $$2\pi$$ with the fourier transform and some use it with inverse fourier transform. Important thing is to use $$2\pi$$ only with one of them