1. IF matrices A, B and C are such that , Show that the inverse of is A
2. In this question i was given 2 matrices A and B . it tells me to work out AB which i know how to do, and then it says hence determine B.
how do i find the inverse of B from the product AB, im thinking i have to use I somewhere, do i make AB = I ?
i would appreciate if you can contribute your thinking process aswell. Im pretty good at all the matix calculations but when i see non standard questions like these which requres thinking, i just don't know where to start from and it really kills my confidence
Thanks!
What is ? What is ?
(To get all of -1 as superscript put it in braces: {-1}.)
What did you get for AB?2. In this question i was given 2 matrices A and B . it tells me to work out AB which i know how to do, and then it says hence determine B.
how do i find the inverse of B from the product AB, im thinking i have to use I somewhere, do i make AB = I ?
i would appreciate if you can contribute your thinking process aswell. Im pretty good at all the matix calculations but when i see non standard questions like these which requres thinking, i just don't know where to start from and it really kills my confidence
Thanks!
Where did you get that these are 3 by 3 matrices? You are not just looking at specific examples are you? And, no, I see nothing here to imply that A is the inverse of B.
You are told that and asked to show that A is the inverse of . Two matrices, X and Y, are inverse to each other if and only if XY= YX= I, the identity matrix. To show that "A is the inverse of ", you need to show that and that [tex](C^{-1}B)A= I[tex].
Of course, and . Use the "associative law" to manipulate those.
For the second problem, you said you were able to find AB but you still have not said what you got.