3. Determine the output y(n) using the convolution sum if 1,x(n)={2,0,n=2,0,1n=1elsewhere and h(n)=(n)(n1)+(n4)+(n5) 4. An LSI system is described by the difference equation y(n)0.5y(n1)+0.25y(n2)=x(n)+2x(n1)+x(n3) (a) Is this system causal? Why? (b) Draw a block diagram of this system. (c) Write a Matlab code to plot the impulse response of this system over 0n100. (d) Check the stability of the system from this plot. (e) If the input to this system is x(n)=[5+3cos(0.2n)+4sin(0.6n)]u(n), plot the response y(n) over 0n100