If A = [(a,x),(y,a)] > and if xy = 1, then det (AA^T) is equal to … (a) (a – 1)^2 (b) (a^2 + 1)^2 (c) a^2 – 1

Question

If A = \(\begin{bmatrix} a&x\\[0.3em]y&a\end{bmatrix}\) > and if xy = 1, then det (AA^T) is equal to …

(a) (a – 1)² 

(b) (a² + 1)² 

(c) a² – 1 

(d) (a² – 1)²

Answer 1

Answer is (d) (a² – 1)²