Plotting discrete time signal

Consider the following difference equation

Y[n-2]+aY[n-1]+bY[n]=x[n-1]+bx[n]

Plot Y[n] if x[n]=5u[n] , b=2,a=0.25 x[n]=u[n-4] , b=2,a=0.25

where u[n] is a unit a step function NOTE: This is a discrete signal. So I shall use the function "stem"

Answer 1

[fuzi tamer]

5(0.75)^n sin(0.1*pi*n) u(n) n=[-20:20]