0.15. An LTI discrete-time system has the impulse response h[n]=(1.2) n u[n] (a) Determine whether this system is causal. (b) Determine whether this system is stable. (c) Find the system response to a unit step input x[n]=u[n]. (d) Use MATLAB to verify the results in (c) for n=0,1,2, and 3 . (e) Repeat Parts (a) through (c) for h[n]=(1.2) n u[−n] (f) Repeat Parts (a) and (b) for h[n](0.3)n u[−n] (g) Repeat Parts (a) and (b) for h[n]=u[−n].