Determine whether each of the following signals is periodic or aperiodic:

a. x(t) = 2eʲ(t+π/4) μt
b. x[n] = μ[n] + μ[-n]
c. x[n] = (1/2)ⁿ μ[n-3]
d. x(t) = e⁽⁻¹⁺ʲ⁾ᵗ