can anybody explain the commented line of the code

fs = 512;

X = [-2 1 -3 5 -1 3 -4 4 -2];
lX = length(X)-1;

Y = -diff(X)/2.*cos(pi*(0:1/fs:1-1/fs)') + (X(1:lX)+X(2:lX+1))/2;
% Y = [Y(:);X(end)];

plot(0:lX,X,'o',0:1/fs:lX,Y)

[madhan ravi]

Are you asking the purpose of it or what the syntax does?

[Nathan Mugge]

What the syntax does

Answer 1

[KALYAN ACHARJYA]

Are you asking this commented line?

% Y=[Y(:);X(end)];

Y(:) represents column vector having all elements (:)

X(end) represents the end element of X

New Y creates the all Y elements and last element of X.

See the following example for better understanding

>> X = [-2 1 -3 5 -1 3 -4 4 -2]

X =

         -2.00          1.00         -3.00          5.00         -1.00          3.00         -4.00          4.00         -2.00

>> Y=[1 2 3 4 5 6 7 8 9]

Y =

          1.00          2.00          3.00          4.00          5.00          6.00          7.00          8.00          9.00

>> Y=[Y(:);X(end)]

Y =

          1.00
          2.00
          3.00
          4.00
          5.00
          6.00
          7.00
          8.00
          9.00
         -2.00

[Maaz Rao]

how can i create a new Y that has all the elements of Y but in row

[madhan ravi]

Y.'

[KALYAN ACHARJYA]

Transpose Y (use ')

X =
         -2.00
          1.00
         -3.00
          5.00
         -1.00
          3.00
         -4.00
          4.00
         -2.00
>> X=X'
X =

         -2.00          1.00         -3.00          5.00         -1.00          3.00         -4.00          4.00         -2.00