Matrices Practice Questions Ques13
Question: If $A = \begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix}$, what is $2A$?
Options:
(A) $\begin{pmatrix} 2 & 4 \\ 6 & 8 \end{pmatrix}$
(B) $\begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix}$
(C) $\begin{pmatrix} 0.5 & 1 \\ 1.5 & 2 \end{pmatrix}$
(D) $\begin{pmatrix} 3 & 6 \\ 9 & 12 \end{pmatrix}$
Show Answer
Answer: A
Explanation:
(A) Correct. Scalar multiplication is performed by multiplying each element by the scalar: $2 \times \begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix} = \begin{pmatrix} 2 & 4 \\ 6 & 8 \end{pmatrix}$.
(B) Incorrect. This is the original matrix $A$.
(C) Incorrect. This is the result of dividing each element by 2.
(D) Incorrect. This is the result of multiplying each element by 3.
BETA
