It's actually REFLECTION about the line y = x.
What transformation matrix represents reflection?
If I get a question in the exam that shows any transformation, and then asks me to find the "2 x 2 matrix which represents the transformation", how would I find it? Is this a case of memorizing specific matrices?
Here's a real question from a past paper:
(a) Describe fully the single transformation which maps triangle A onto triangle B.
Rotation, y = x
(b) Find the 2 × 2 matrix which represents this transformation.
Oh ok, a = 0 and b = 1. So you basically just assigned two random values to a and b?
Sorry Im asking so many questions. I understand the basics of matrices (addition, multiplication, determinants, inverse) but transformational matrices seem to go over my head, and my textbook is terrible at explaining it.
No we did not assign two random values to a and b. For the equation to be balanced, the x_1 terms have to have the same coefficients, and the x_2 terms have to have the same coefficients.
So if ax_1 + bx_2 = x_2, there is clearly a zero x_1 term. So a = 0 and b = 1.