The size of two matrices is given. Find the size of the product AB and the product BA, if the products exist.
-A is 3 × 1, B is 3 × 1.
A) AB is 1 × 3, BA is 3 × 1.
B) AB is 3 × 3, BA is 1 × 1.
C) AB is 3 × 1, BA is 1 × 3.
D) AB is undefined, BA is undefined.

Question

Quizplus · Accepted Answer

Matrix multiplication is only possible if the number of columns in the first matrix is equal to the number of rows in the second matrix. Since both matrices A and B are 3 × 1, neither AB nor BA can be computed due to incompatible dimensions.

The Size of Two Matrices Is Given