v1 = [1; 2]
v2 = [3; 1]
v1 + v2
v3 = 2*v1
v4 = 2*v1 - 3*v3
v5 = [-1 1 3 4 6]
v5(1) % it gives me the element in position 1
v5(2) % it gives me the element in position 2
v5(5) % it gives me the element in position 5
length(v5) % it gives me the length of the array
numel(v5) % it gives me the number of elements of the array
v5(length(v5)) % it gives me the element in the last position
v5(numel(v5)) % it gives me the element in the last position
v5(end) % it gives me the element in the last position
v5(end - 1) % it gives me the element in the next to last position
v5([2 4 5]) % it gives me the elements in position 2, 4, and 5.
v5(2) = [] % it deletes the element in position 2
v5([1 4]) = [] % it deletes the elements in position 1 and 4
v5 = [[2 3], v5, -1] %{ concatenate v5 with the vector [2 3] before it 
                    % and -1 after it
v5 = v5 - 1 % it subtracts 1 to each element of the array
v6 = v5.^2 % elementswise power or 
% v6 = power(v5, 2)
% Other examples
sqrt(81)
sqrt([25, 16, 9])