Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main202225 Jul 2022Morning ShiftMathematicsMatricesActual

Let A = 2 - 1 - 1 1 0 - 1 1 - 1 0 and B = A - I . If ω = 3 i - 1 2 , then the number of elements in the set n ∈ 1 , 2 , … , 100 : A n + ω B n = A + B is equal to _____ .

Correct answer

0

Step-by-step solution

Given, A = 2 - 1 - 1 1 0 - 1 1 - 1 0 ⇒ A 2 = 2 - 1 - 1 1 0 - 1 1 - 1 0 2 - 1 - 1 1 0 - 1 1 - 1 0 = 2 - 1 - 1 1 0 - 1 1 - 1 0 = A ⇒ A n = A Now ∀ n ∈ 1 , 2 , … , 100 Now, B = A - I = 1 - 1 - 1 1 - 1 - 1 1 - 1 - 1 B 2 = 1 - 1 - 1 1 - 1 - 1 1 - 1 - 1 1 - 1 - 1 1 - 1 - 1 1 - 1 - 1 = - 1 - 1 - 1 1 - 1 - 1 1 - 1 - 1 = - B ⇒ B 3 = - B 2 = B ⇒ B 5 = B ⇒ B 99 = B Also, ω 3 k = 1 So, n = common of 1 , 3 , 5 , … , 99 and 3 , 6 , 9 , … , 99 = 17

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