The Fourier transform of a function is ˆu(⇠) = 1 for ⇠ 2 [⇡, ⇡] and zero elsewhere. Calculate u(x).

The Fourier transform of a function is ˆu(⇠) = 1 for ⇠ 2 [⇡, ⇡] and zero elsewhere. Calculate u(x).