= : Q.1: Determine the Z-transform of the discrete-time sequences sampled from the following continuous- time functions at To = 0.5 s and u(t) is the unit step function at t = 0. 1. f(t) = 0.4 cos (0.8t) u(t) 2. f(t) = -0.4t Rei5t)u(t) where R(a) denotes the real part of complex number a, e.g., if a= a + i, then R(a) = R(a +iB) = a. 3. f(3) = 8+2 8(8+5) 4. f(t) = u(t) - zu(t)