Engineering Mathematics Miscellaneous


Engineering Mathematics Miscellaneous

Engineering Mathematics

  1. A is a 3 × 4 real matrix and Ax = b is an inconsistent system of equations. The highest possible rank of A is









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    C = [A: B]3 × 5
    ∴ ρ [C3 × 5 ] <e; min [3,5}
    Since the system is inconsistent
    ρ(A) < ρ(C)
    ∴ ρ (A) < 3
    Hence, the maximum possible rank of A = 2

    Correct Option: C

    C = [A: B]3 × 5
    ∴ ρ [C3 × 5 ] <e; min [3,5}
    Since the system is inconsistent
    ρ(A) < ρ(C)
    ∴ ρ (A) < 3
    Hence, the maximum possible rank of A = 2


  1. Consider the system of simultaneous equations
    x + 2y + z = 6
    2x + y + 2z = 6
    x + y + z = 5
    This system has









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    Given equations are
    x + 2y + z = 6
    2x + y + 2z = 6
    x + y + z = 5
    Given system can be written as

    Applying row operation
    R2 → R2 – 2R1, R3 → R3 – R1

    and applying R3 → 3R3 – R1

    Since the rank of co-efficient matrix is 2 and rank of argument matrix is 3, which is not equal. Hence system has no solution.

    Correct Option: C

    Given equations are
    x + 2y + z = 6
    2x + y + 2z = 6
    x + y + z = 5
    Given system can be written as

    Applying row operation
    R2 → R2 – 2R1, R3 → R3 – R1

    and applying R3 → 3R3 – R1

    Since the rank of co-efficient matrix is 2 and rank of argument matrix is 3, which is not equal. Hence system has no solution.



  1. If then det(A–1) is _________. (correct to two decimal places).









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    |A| = 4
    = 4

    |A–1| =
    1
    =
    1
    = 0.25
    |A|4

    Correct Option: D


    |A| = 4
    = 4

    |A–1| =
    1
    =
    1
    = 0.25
    |A|4


  1. The determinant of a 2 × 2 matrix is 50. If one eigenvalue of the matrix is 10, the other eigen value is ________.









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    The product of eigen value of any matrix is equal to the determinant value of the matrix λ1 = 10 , λ2 = unknown
    |A| = 50
    λ12 = 50
    10(λ2) = 50
    ∴ λ2 = 5

    Correct Option: B

    The product of eigen value of any matrix is equal to the determinant value of the matrix λ1 = 10 , λ2 = unknown
    |A| = 50
    λ12 = 50
    10(λ2) = 50
    ∴ λ2 = 5



  1. For given matrix P = 4 + 3i-i where i = √-1, the inverse of matrix P is
    i4 - 3i










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    P = 4 + 3i-i
    i4 - 3i

    P-1 = 4 - 3i-(-i)
    -i4 + 3i
    | A |

    =
    1
    4 - 3ii
    24-i4 + 3i

    Correct Option: A

    P = 4 + 3i-i
    i4 - 3i

    P-1 = 4 - 3i-(-i)
    -i4 + 3i
    | A |

    =
    1
    4 - 3ii
    24-i4 + 3i