Use the windowing method to design a length$-81$ low$-$pass GLP FIR filter with cut$-$off frequency

$.$

a$)$ Should the filter have Type $1$ of Type $2$ GLP$?$

b$)$ Find an expression for the filter coefficients if the truncation window is used for

the design.

c$)$ Find an expression for the filter coefficients if the Hamming window is used for the

design.

d$)$ Comment on the choice of the truncation and Hamming windows.