# 17.&nbsp; Let x(t)= cos(10πt)+cos(30πt) be sam...

17.  Let x(t)= cos(10πt)+cos(30πt) be sampled at 20 Hz and reconstructed using an ideal lowpass filter with cut-off frequency of 20 Hz. The frequency/frequencies present in the reconstructed signal is/are

(A) 5 Hz and 15 Hz only

(B) 10 Hz and 15 Hz only

(C) 5 Hz, 10 Hz and 15 Hz only

(D) 5 Hz only

Hint:
Explanation:

Answer-(A) 5 Hz and 15 Hz only
Discuss the solution.