Find DTFT \(X(\Omega )\) of \(x[n]= \sin (\frac {\pi n}{8})\). By deļ¬nition \begin {align*} X(\Omega ) &= \sum _{n=-\infty }^{\infty } x[n] e^{-i\Omega n} \end {align*}
Mathematica
Clear["Global`*"]; x[n_] := Sin[(Pi*n)/8]; X = FourierSequenceTransform[x[n], n, w, FourierParameters -> {1, 1}] // Simplify
Which gives
(-(1/2))*I*(DiracComb[(Pi - 8*w)/(16*Pi)] - DiracComb[(Pi + 8*w)/(16*Pi)])