Chapter 6.CR, Problem 99CR

True or False? In Exercises 99-102, determine whether each statement is true or false. If a statement is true, give a reason or cite an appropriate statement from the text. If a statement is false, provide an example that shows the statement is not true in all cases or cite an appropriate statement from the text.

(a) Reflection that map a point in the xy-plane to its mirror image across the line $y=x$ are linear transformations that are defined by the matrix $\left[\begin{array}{cc}1& 0\\ 0& 1\end{array}\right]$.

(b) Horizontal expansions or contractions are linear transformations that are defined by the matrix $\left[\begin{array}{cc}k& 0\\ 0& 1\end{array}\right]$.