Problem 2. Determine the impulse response for the following systems, classify each system as either an FIR or IIR, and plot each impulse response in MATLAB for n=0, 1,2, .,

20. \text { a. } y[n]=2 x[n]-x[n-1]+0.5 x[n-2] \text { b. } y[n]=x[n]-0.5 x[n+1]-0.5 x[n-1] \text { c. } y[n]=\sum_{k=0}^{4}\left(\frac{1}{k+1}\right) x[n-k] \text { d. } y[n]=x[n]+y[n-1], \text { where } y[-1]=0.5 \text { . } \text { e. } y[n]=x[n]+y[n-1]-2 y[n-2], \text { where } y[-1]=1 \text { and } y[-2]=0