Question #$8$:

We are given a discrete$-$time LTI system with the impulse response,

$h_1[n]=h[n]*u[n-1]$

a$)$ Sketch $h_1[n],$

b$)$ Is the system causal? Why$/$why not?

c$)$ Is it stable? Why $/$ why not?

d$)$ Suppose we connect two such systems in series $($cascaded$).$ Derive or sketch the impulse response $h_2[n]$ of the combined svstem. Is $h_2[n]$ causal? Why$/$why not?