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Matrices

Question

If P = $open square brackets table row 1 straight alpha 3 row 1 3 3 row 2 4 4 end table close square brackets$ is the adjoint of a 3 x3 matrix A and |A| = 4, then α is equal to

4

11

5

0

Solution

Given,
$straight P space equals space open square brackets table row 1 straight alpha 3 row 1 3 3 row 2 4 4 end table close square brackets$
|P| = 1(12-12)-α (4-6) +3(4-6)
= 2α -6.
∵ P =adj(A)
∴ |P| = |adj A | = |A|3-1 = |A|2 = 16
[∵ |adj A| = |A|n-1 order is 3 x3
∴ 2α -6 = 16
2α = 22
α = 11

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Matrices

If P = $open square brackets table row 1 straight alpha 3 row 1 3 3 row 2 4 4 end table close square brackets$ is the adjoint of a 3 x3 matrix A and |A| = 4, then α is equal to

4

11

5

0

Some More Questions From Matrices Chapter

If a matrix A has 12 elements, what arc the possible orders it can have 7 What if it has 7 elements ?

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For Daily Free Study Material Join wiredfaculty

Matrices

If P = is the adjoint of a 3 x3 matrix A and |A| = 4, then α is equal to 4 11 5 0

Some More Questions From Matrices Chapter

If a matrix A has 12 elements, what arc the possible orders it can have 7 What if it has 7 elements ?

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

If P = $open square brackets table row 1 straight alpha 3 row 1 3 3 row 2 4 4 end table close square brackets$ is the adjoint of a 3 x3 matrix A and |A| = 4, then α is equal to

4

11

5

0