Part A
I used sin(t) for CT periodic signal which frequency is 50hz.
For DT periodic signals, I fix ts at 1000hz.
For DT nonperiodic signals, I fix ts at 164hz.
Part B
I picked x^2 as a non-periodic signal.
Here is a picture of the signal.
Period is 4.
Here is a picture of a peridic signal with T=4
