Solution

Past exam of the mathematics course of the University of Cambridge / 2005 / iii / Paper 87 / 3 / Solution

Past exam of the mathematics course of the University of Cambridge / 2018 / ii / Paper 4 / 40E / d / i / Solution

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The inverse discrete Fourier transform reconstructs samples from their <discrete Fourier transform>. Under one common normalization,
$$
x_\ell=\frac1n\sum_{j=0}^{n-1}Y_je^{2\pi i j\ell/n};
$$
moving the factor $1/n$ between the forward and inverse transforms gives other standard conventions.

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