This was the question on my today's exam on signals and systems:
*We have a continuous function $f(t)$. Its value of the spectral function at an angular frequency of $8000\pi\ rad/s$ is $\frac{1}{32000}e^{j\frac{\pi}{4}}$.
Afterwards, the same signal is sampled at sampling frequency $64000\pi\ rad/s$. Aliasing did not occur. Determine whether it is possible to tell the value of the spectral function of the sampled signal at an angular frequency of $72000\pi\ rad/s$.*
I realized that the maximum frequency I can recover from the signal is $32000\pi$ rad/s. Therefore, I said that we could not recover the spectral function value at angular frequency of $72000\pi$ rad/s.
The correct answer, however, was $e^{j\frac{\pi}{4}}$. I don't see an error in what I said, so I will appreciate any push towards the right answer. Thank you.