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Determinants

Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.

Determinant of a square matrix (up to 3 x 3 matrices)

Subtopic

Determinant of a square matrix (up to 3 x 3 matrices) under Determinants for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    The value of ∣sin⁡2θcos⁡2θ−11∣\begin{vmatrix} \sin^2 \theta & \cos^2 \theta \\ -1 & 1 \end{vmatrix} is:

    A.

    0

    B.

    2sin⁡2θ2 \sin^2 \theta

    C.

    1

    D.

    cos⁡2θ\cos 2\theta

  2. 2.

    Evaluate: ∣1ωωω2∣\begin{vmatrix} 1 & \omega \\ \omega & \omega^2 \end{vmatrix} where ω\omega is a complex cube root of unity.

    A.

    0

    B.

    1

    C.

    ω\omega

    D.

    ω2\omega^2

  3. 3.

    If AA is a 3×33 \times 3 matrix and ∣A∣=k|A| = k, then ∣−2A∣|-2A| is:

    A.

    -2k

    B.

    4k

    C.

    -8k

    D.

    8k

Download the worksheet for Determinants - Determinant of a square matrix (up to 3 x 3 matrices) to practice offline. It includes additional chapter-level practice questions.

Minors, co-factors and applications of determinants in finding the area of a triangle

Subtopic

Minors, co-factors and applications of determinants in finding the area of a triangle under Determinants for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Find the minor M32M_{32} of the determinant ∣2−3560415−7∣\begin{vmatrix} 2 & -3 & 5 \\ 6 & 0 & 4 \\ 1 & 5 & -7 \end{vmatrix}.

    A.

    −22-22

    B.

    2222

    C.

    1414

    D.

    −14-14

  2. 2.

    What is the minor of the element 77 in the determinant ∣123456789∣\begin{vmatrix} 1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & 9 \end{vmatrix}?

    A.

    −3-3

    B.

    33

    C.

    1515

    D.

    −15-15

  3. 3.

    Find the area of a triangle with vertices (3,8)(3, 8), (−4,2)(-4, 2), and (5,1)(5, 1).

    A.

    30.530.5 sq units

    B.

    6161 sq units

    C.

    3030 sq units

    D.

    1515 sq units

Download the worksheet for Determinants - Minors, co-factors and applications of determinants in finding the area of a triangle to practice offline. It includes additional chapter-level practice questions.

Adjoint and inverse of a square matrix

Subtopic

Adjoint and inverse of a square matrix under Determinants for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If AA is a square matrix of order 4 and ∣A∣=2|A| = 2, then ∣adj A∣|\text{adj } A| is:

    A.

    4

    B.

    8

    C.

    16

    D.

    2

  2. 2.

    If AA is an identity matrix of order nn, then ∣adj A∣|\text{adj } A| is:

    A.

    nn

    B.

    0

    C.

    1

    D.

    n2n^2

  3. 3.

    If adj A=[2345]\text{adj } A = \begin{bmatrix} 2 & 3 \\ 4 & 5 \end{bmatrix}, then adj (AT)\text{adj }(A^T) is:

    A.

    [2435]\begin{bmatrix} 2 & 4 \\ 3 & 5 \end{bmatrix}

    B.

    [5342]\begin{bmatrix} 5 & 3 \\ 4 & 2 \end{bmatrix}

    C.

    [2345]\begin{bmatrix} 2 & 3 \\ 4 & 5 \end{bmatrix}

    D.

    [−2−3−4−5]\begin{bmatrix} -2 & -3 \\ -4 & -5 \end{bmatrix}

Download the worksheet for Determinants - Adjoint and inverse of a square matrix to practice offline. It includes additional chapter-level practice questions.

Solving system of linear equations using inverse of a matrix

Subtopic

Solving system of linear equations using inverse of a matrix under Determinants for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    The matrix product A⋅A−1A \cdot A^{-1} results in:

    A.

    Matrix AA

    B.

    Matrix OO (Null)

    C.

    Matrix II (Identity)

    D.

    Matrix BB

  2. 2.

    Identify the element a12a_{12} in the coefficient matrix AA for the system 2x+5y=102x + 5y = 10 and 3x−y=43x - y = 4.

    A.

    2

    B.

    5

    C.

    3

    D.

    -1

  3. 3.

    A system of equations AX=BAX = B is consistent if ∣A∣=2|A| = 2. How many solutions does it have?

    A.

    None

    B.

    Exactly one

    C.

    Exactly two

    D.

    Infinite

Download the worksheet for Determinants - Solving system of linear equations using inverse of a matrix to practice offline. It includes additional chapter-level practice questions.

Determinant of a matrix of order one

Subtopic

Determinant of a matrix of order one under Determinants for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If the determinant of [2x][2x] is 1010, what is the value of xx?

    A.

    1010

    B.

    22

    C.

    55

    D.

    2020

  2. 2.

    Find the determinant of the matrix M=[−1]M = [-1].

    A.

    11

    B.

    −1-1

    C.

    00

    D.

    ii

  3. 3.

    If A=[x−5]A = [x - 5], find ∣A∣|A|.

    A.

    xx

    B.

    55

    C.

    x−5x-5

    D.

    5−x5-x

Download the worksheet for Determinants - Determinant of a matrix of order one to practice offline. It includes additional chapter-level practice questions.

Determinant of a matrix of order two

Subtopic

Determinant of a matrix of order two under Determinants for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Evaluate ∣1a01∣\begin{vmatrix} 1 & a \\ 0 & 1 \end{vmatrix}.

    A.

    0

    B.

    1

    C.

    a

    D.

    1-a

  2. 2.

    If ∣A∣=5|A| = 5 and AA is a 2×22 \times 2 matrix, what is the value of ∣3A∣|3A|?

    A.

    15

    B.

    45

    C.

    5

    D.

    9

  3. 3.

    Find the value of ∣sin⁡40∘−cos⁡40∘sin⁡50∘cos⁡50∘∣\begin{vmatrix} \sin 40^\circ & -\cos 40^\circ \\ \sin 50^\circ & \cos 50^\circ \end{vmatrix}.

    A.

    0

    B.

    -1

    C.

    1

    D.

    cos⁡10∘\cos 10^\circ

Download the worksheet for Determinants - Determinant of a matrix of order two to practice offline. It includes additional chapter-level practice questions.

Determinant of a matrix of order 3 × 3

Subtopic

Determinant of a matrix of order 3 × 3 under Determinants for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Evaluate ∣1234812567∣\begin{vmatrix} 1 & 2 & 3 \\ 4 & 8 & 12 \\ 5 & 6 & 7 \end{vmatrix}.

    A.

    0

    B.

    1

    C.

    24

    D.

    -12

  2. 2.

    If ∣A∣=−5|A| = -5 for a 3×33 \times 3 matrix, find ∣−A∣|-A|.

    A.

    5

    B.

    -5

    C.

    15

    D.

    -15

  3. 3.

    Calculate ∣1xy02z003∣\begin{vmatrix} 1 & x & y \\ 0 & 2 & z \\ 0 & 0 & 3 \end{vmatrix}.

    A.

    1

    B.

    6

    C.

    x+y+z

    D.

    0

Download the worksheet for Determinants - Determinant of a matrix of order 3 × 3 to practice offline. It includes additional chapter-level practice questions.

Area of a Triangle

Subtopic

Area of a Triangle under Determinants for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Area of a triangle with vertices (a,0)(a, 0), (0,b)(0, b), and (0,0)(0, 0) is:

    A.

    abab

    B.

    12ab\frac{1}{2}ab

    C.

    12∣ab∣\frac{1}{2}|ab|

    D.

    ∣ab∣|ab|

  2. 2.

    Find the area of the triangle with vertices (1,0)(1, 0), (6,0)(6, 0), and (4,3)(4, 3) using the formula Δ=12∣x1(y2−y3)+x2(y3−y1)+x3(y1−y2)∣\Delta = \frac{1}{2} |x_1(y_2 - y_3) + x_2(y_3 - y_1) + x_3(y_1 - y_2)|.

    A.

    7.57.5

    B.

    1515

    C.

    8.58.5

    D.

    1010

  3. 3.

    Which of the following represents the area of a triangle with vertices (x1,y1)(x_1, y_1), (x2,y2)(x_2, y_2), and (x3,y3)(x_3, y_3)?

    A.

    ∣x1y11x2y21x3y31∣\begin{vmatrix} x_1 & y_1 & 1 \\ x_2 & y_2 & 1 \\ x_3 & y_3 & 1 \end{vmatrix}

    B.

    12∣x1y11x2y21x3y31∣\frac{1}{2} \begin{vmatrix} x_1 & y_1 & 1 \\ x_2 & y_2 & 1 \\ x_3 & y_3 & 1 \end{vmatrix}

    C.

    ∣12∣x1y11x2y21x3y31∣∣\left| \frac{1}{2} \begin{vmatrix} x_1 & y_1 & 1 \\ x_2 & y_2 & 1 \\ x_3 & y_3 & 1 \end{vmatrix} \right|

    D.

    12∣x1x2x3y1y2y3111∣2\frac{1}{2} \begin{vmatrix} x_1 & x_2 & x_3 \\ y_1 & y_2 & y_3 \\ 1 & 1 & 1 \end{vmatrix}^2

Download the worksheet for Determinants - Area of a Triangle to practice offline. It includes additional chapter-level practice questions.

Adjoint of a matrix

Subtopic

Adjoint of a matrix under Determinants for Grade 12 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If A=[123014001]A = \begin{bmatrix} 1 & 2 & 3 \\ 0 & 1 & 4 \\ 0 & 0 & 1 \end{bmatrix}, then the determinant of its adjoint is:

    A.

    1

    B.

    0

    C.

    12

    D.

    9

  2. 2.

    If AA is a matrix of order 3×33 \times 3, then adj(A2)adj(A^2) is equal to:

    A.

    (adjA)2(adj A)^2

    B.

    2adjA2 adj A

    C.

    ∣A∣adjA|A| adj A

    D.

    A(adjA)A(adj A)

  3. 3.

    If AA is a 2×22 \times 2 matrix and A(adjA)=10IA(adj A) = 10I, then ∣A∣|A| is:

    A.

    10

    B.

    100

    C.

    5

    D.

    1

Download the worksheet for Determinants - Adjoint of a matrix to practice offline. It includes additional chapter-level practice questions.