JEE Main 2015Session, Shift 1MathematicsHardMatrices and Determinants245× since 2002If A=[12221−2a2b]A = \left[ {\matrix{ 1 & 2 & 2 \cr 2 & 1 & { - 2} \cr a & 2 & b \cr } } \right]A=12a2122−2b is a matrix satisfying the equation AAT=9I,A{A^T} = 9\text{I},AAT=9I, where III is 3×33 \times 33×3 identity matrix, then the ordered pair (a,b)(a, b)(a,b) is equal to :AOption A. (2,1)(2, 1)(2,1)BOption B. (−2,−1)(-2, -1)(−2,−1)COption C. (2,−1)(2, -1)(2,−1)DOption D. (−2,1)(-2, 1)(−2,1)CheckSkip · show solution
