Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE MainMathematicsMatrices

Let A = bmatrix & 3 & - bmatrix where , Z . It is given that (A) = -1 and - 2 = 4 . The sum of all elements of the matrix (A+I)¹⁰ , where I is the 2 2 identity matrix, is:

Options

  1. A4
  2. B2048
  3. C4096
  4. D22

Correct answer

B. 2048

Step-by-step solution

Given A = bmatrix & 3 & - bmatrix , we have (A) = - ^2 - 3 = -1 . We are also given - 2 = 4 = 2 + 4 . Substituting into the determinant equation: -(2 + 4)^2 - 3 = -1 -(4 ^2 + 16 + 16) - 3 + 1 = 0 4 ^2 + 19 + 15 = 0 (4 + 15)( + 1) = 0 Since Z , we must have = -1 . Then = 2(-1) + 4 = 2 . Thus, A = bmatrix 2 & -1 3 & -2 bmatrix . Observe that tr (A) = 0 and (A) = -1 . By the Cayley-Hamilton theorem, A^2 - tr (A)A + (A)I = 0 A^2 - I = 0 A^2 = I . Now, consider (A+I)^2 = A^2 + 2A + I . Since A^2 = I , this becomes I + 2

Practice Matrices on Quantrex Academy →

More from Matrices

Which one of the following matrices can be obtained by performing elementary row transformations on the 3 3 identity matrix? 2026Consider the matrix M = bmatrix 2 & -1 1 & 0 bmatrix . Let p, q, r, s, a, b, c and d be integers such that M²⁶ = bmatrix p & q r & s bmatrix and _ k=1 ²⁶ M^k = bmatrix a & b c & d 2026For real numbers , , , and , consider the matrix M = bmatrix & 1 2 & - 1 2 1 3 & & 1 3 & & bmatrix . Suppose that MM^T = I , where M^T is the transpose of the matrix M , and I is t 2026Let R denote the set of all real numbers and let i = -1 . Consider the matrices S = bmatrix 0 & -1 1 & 0 bmatrix and T = bmatrix 1 & 1 0 & 1 bmatrix . Let a, b, c, d be real number 2026Let A = bmatrix & 1 & 2 2 & 3 & 0 0 & 4 & 5 bmatrix and B = bmatrix 1 & 0 & 0 0 & -5 & 0 0 & 4 & -2 bmatrix + adj (A) . If (B)=66 , then ( adj (A)) equals: 2026Let A = bmatrix 1 & 0 & 0 3 & 1 & 0 9 & 3 & 1 bmatrix and B = [b_ ij ] , 1 i, j 3 . If B = A⁹⁹ - I , then the value of b₃₁ - b₂₁ b₃₂ is : 2026Let A = bmatrix -1 & 1 & -1 1 & 0 & 1 0 & 0 & 1 bmatrix satisfy A^2 + (adj(adj(A))) + (adj(A)(adj(adj(A)))) = bmatrix 2 & -2 & 2 -2 & 0 & -1 0 & 0 & -1 bmatrix for some , R . Then 2026Let M be a 3 3 matrix such that M pmatrix 1 0 0 pmatrix = pmatrix 1 2 3 pmatrix , M pmatrix 0 1 0 pmatrix = pmatrix 0 1 2 pmatrix and M pmatrix 0 0 1 pmatrix = pmatrix -1 1 1 pmatr 2026 Full Matrices list All JEE Main PYQs