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Find the determinant of a matrix B when A is a 4x4 matrix with a neg. determinant (Linear Algebra)?

I am looking for hints to help me solve this problem. Thanks.

Let A be a 4x4 orthogonal matrix whose determinant is negative. What is the value of |B|, where B = (2*adj(A))^(-1)?

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  • 1 decade ago
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    If A is an orthogonal matrix with a negative determinant then its determinant must be negative one because orthogonal matrices always have a determinant of one or negative one. Since you are multiplying a 4x4 matrix with 2, the determinant is multiplied by 2^4=16 so the determinant is now -16. And then you take the matrix's inverse which means that you take the inverse of the determinant also. So the determinant of B is -1/16.

  • 1 decade ago

    I'm rusty but I think the answer is in the question itself... take a carefull look and see what you can do. or rather what you cant do.

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