Question
Question: Matrix M<sub>r</sub> is defined as M<sub>r</sub> =\(egin{bmatrix} r & r–1 \ r–1 & r \\end{bmatrix}\...
Matrix Mr is defined as Mr =egin{bmatrix} r & r–1 \ r–1 & r \\end{bmatrix}, r Ī N. Then det. (M1) + det.(M2) + ........... + det.(M2009) = ?
A
2009
B
(2009)2
C
(2009)3
D
None of these
Answer
(2009)2
Explanation
Solution
det.(Mr) = r2 – (r –1)2 = 2r –1
∑r=12009(2r–1) = 2 × (22009×2010) – 2009
= (2009) × (2009) = (2009)2