Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main202312 Apr 2023Morning ShiftMathematicsMatricesActual

Let A = 1 1 51 0 1 . If B = 1 2 - 1 - 1 A - 1 - 2 1 1 , then the sum of all the elements of the matrix ∑ n = 1 50 B n is equal to

Options

  1. A75
  2. B125
  3. C50
  4. D100

Correct answer

D. 100

Step-by-step solution

Given, A = 1 1 51 0 1 , B = 1 2 - 1 - 1   A - 1 - 2 1 1 So, B = M A N Now let M = 1 2 - 1 - 1   &   N = - 1 - 2 1 1 Now solving, 1 2 - 1 - 1 M   - 1 - 2 1 1 N = 1 0 0 1 ∴   M N = I = N M Now using, B = M A N we get B n = M A N n = M A N   M A N   . . . . . . . M A N   ⇒ B n = M A N M ⏟ I A N M ⏟ I   . . . . . . . N M ⏟ I A N   ⇒ B n = M A A A A A . . . . . A ⏟ n   times N   = M A n N Now, using A = 1 1 51 0 1 &

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