Question

If the variable A has been defined as a 3 by 4 matrix, the 2nd row can be removed using which of the following commands.

a. A = remove(A, 2, 'row');
b. A(2, :) = [];
c. A = deleteRow(A, 2);
d. A = dropRow(A, 2);

Answer 1

The command to remove the 2nd row from a 3 by 4 matrix named A is 'A(2, :) = [];'. This syntax selects the entire second row and assigns it an empty array, effectively deleting it.

Step-by-step explanation:

If the variable A has been defined as a 3 by 4 matrix, the command to remove the 2nd row is A(2, :) = [];. This is because in most matrix-oriented programming languages such as MATLAB or Octave, you can remove a row or a column by assigning it an empty array. Let's go through the syntax: A(2, :) refers to the second row of matrix A, with the colon (:) indicating all columns in that row. By setting this equal to an empty array ([]), you essentially delete the entire row.