Fourier Transform of delta functions
$ x(t) = \delta (t+1) + \delta (t-1) $
$ X(\omega) = \int_{-\infty}^{\infty} \delta (t+1)e^{-j \omega t} + \int_{-\infty}^{\infty} \delta (t-1)e^{-j \omega t} dt $
$ X(\omega} = e^{j \ omega}+ e^{-j \omega} = \frac{1}{2} (e^ {j \ omega} + e^ {-j \ omega})^2 $
