7. For $x[n] = [1, 2, 4, 1]$, a 4-point DFT $X[k]$ provide a 4-point frequency sampling between 0 and $2\pi$. If
we would like to observe a high-resolution frequency response, we obtain $X_2[k]$ by performing an 8-point
DFT of $x[n]$.
(a) Should we obtain How to obtain $X_2[k]$ by perform DFT of $[1,2,4,1,0,0,0,0]$ or $[0,0,0,0,1,2,4,1]$? Or it
does not matter?
(b) What is the relationship between $X[k]$ and $X_2[k]$?