hi all just got stuck on these questions on matrices just wondering if anyone can help me out thanks(adsbygoogle = window.adsbygoogle || []).push({});

1. For which values of k is the folowing equation satisfied?

|3-k 5 |

= 0

|4 4-k |

its all in a matrix. im thinking it is the determinant =0 so

(3-k)(4-k) - 20 = 0

12-7k-k^2 - 20 = 0

-k^2-7k-44=0

then we solve for k? thats out ans?

2. IF A is a matrix or order 2x1, B is 2x3 and C is 3x3 which of the folowing is defined?

a) ABC

b) AT B ( a is transposed * B)

c) BCT + AT (B*Ctransposed + Atransposed)

well i know a) cannot be defined since when you multiply matrices must be the order ie 2x1 * 1x3 etc but wont work

b) can be defined

c) confused since adding matrices not sure how that works.

please reply

thanks

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# Matrices hard!

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