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**MajikWaffle****Member**- Registered: 2005-12-14
- Posts: 11

Let A = 5 9

2 7

and B = 1 8

3 6

Find the standard matrix C of the linear transformation T(x) = B(A(x)).

And then

Determine which of the formulas hold for all invertible *n*×*n* matrices A and B

A. A5 is invertible

B. (ABA−1)8 = AB8A−1

C. (A+B)(A−B) = A2−B2

D. (A+A−1)3 = A3+A−3

E. A+In is invertible

F. ABA−1 = B

And finally

Which of the following linear transformations from R3 to R3

are invertible?

A. Projection onto the xz -plane

B. Projection onto the x -axis

C. Rotation about the z -axis

D. Identity transformation (i.e. T(v) = v for all v)

E. Dilation by a factor of 6

F. Reflection in the y -axis

>_> Too hard.

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