CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon


Question

If A is orthogonal matrix of order 2 then det(adj 2A) =

(a) 4   (b) 16.  (c) 27   (d) 64


Solution

We know that,
det of an orthogonal matrix = -1 or +1
det (A) = +1 or -1
Since A is of order 2,
det (2A) = 4×det (A)
= +4 or -4

Also we know the formula,
det (adj A)
= [det (A)]^n-1
where n is the order of the matrix.

So, det (adj 2A)
=  [det (2A)]^2-1
= 4^1 or (-4)^1
= +4 or -4

Answer is option (a) 4
 

flag
 Suggest corrections
thumbs-up
 
0 Upvotes


Similar questions
QuestionImage
QuestionImage
View More...



footer-image