Part A
Basically, since all of the examples are the same i chose a random person and that random person was Nicholas Block and he had cos(2t).
x[n]=cos(2n) is not periodic because there needs to be a factor of 2pi and since n is an integer, there is not going to be a period.
x(t)=cos(2t) is periodic everytime t has a factor of 2pi.
