Question

The blue triangle has been reflected to the red triangle. Choose the matrix which made this transformation.

Answer 1

B)
`\left[\begin{array}{cc}1&0\\0&-1\end{array}\right]`

Explanation:

When the coordinates are represented by a column vector, the vertical reflection transformation (x, y) ⇒ (x, -y) looks like the matrix of answer choice B.