Hello

I am working on a question from a textbook about a matrix transformation. Here is the question:

I have completed the question but I disagree with the answer given in the back of the book forpart (b).

I have worked out that the transformation represents areflection in the line y=5^(-0.5) x followed by an enlargement scale factor 3.

However the book says it is areflection in the line y=x tan 48.2 followed by an enlargement scale factor 3.

I have double checked my work and am sure I am correct. Could someone please look at my working and advise who is correct? Many thanks for looking at this.

Here is my working: