(9) (?) (3) Let ei = and e2 = Let T be the linear transformation which sends e, to ( ) and sends e2 to (a) Find the image of ( -3 and X2 (b) What is the standard matrix of T? (4) Let T : R² → R² be the linear transformation given by r(:)-(, (:) xi + x2 4x1 + 5x2 T X2 3 Find x such that Tx = 8

-2 Use a rectangular coordinate system to plot u = ,v = 1, and their images under the 4 -1 given transformation T(x) = | Describe geometrically what T does to each vector in R2.

2. Let A = be an orthogonal 2 × 2 matrix. cos(0) sin(0 (a) Explain why the vector can be written as for some value of 0. a Use your answer to part (a) to find all 2×2 orthogonal matrices A = |C (b) (Hint: What can the second column of A look like?) (c) det(A) = 1? What kind of linear transformation do they correspond to? ! Given your answer to part (b), what are the 2 × 2 orthogonal matrices with

Cross product is a linear transformation from R³ →R³ You can define it as X1 X2 X3 X Yı Y2 Y3 e₁ X1 Y1 x2 Y2 Y3 = = det( e2 → ez X3 Note that this is the determinant of a matrix that has vectors as some of the entries. You can look at section 3.6 in the textbook for alternate definitions. Define the linear transformation Tas T(x) = x x 2 3 a. Compute T(ei), T(₂), Te) b. Use your answer from a. to write the standard matrix of the linear transformation T c. Use your answer from b. to compute T( 4 H 3