MathematicsMatrices

    If A=(1234)A = \begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix}, then A+ATA + A^T equals:

    A

    (2558)\begin{pmatrix} 2 & 5 \\ 5 & 8 \end{pmatrix}

    B

    (1554)\begin{pmatrix} 1 & 5 \\ 5 & 4 \end{pmatrix}

    C

    (2468)\begin{pmatrix} 2 & 4 \\ 6 & 8 \end{pmatrix}

    D

    (0110)\begin{pmatrix} 0 & 1 \\ -1 & 0 \end{pmatrix}

    Answer(Detailed Solution Below)Option A :

    (2558)\begin{pmatrix} 2 & 5 \\ 5 & 8 \end{pmatrix}

    Recommended Test Series

    RRB NTPC CBT-1 Special

    Free Demo

    Focus on GA & Arithmetic. Sectional + full mock tests.

    45k students enrolled

    Start Test

    Step-by-step Solution:

    Given: A=(1234)A = \begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix}

    AT=(1324)A^T = \begin{pmatrix} 1 & 3 \\ 2 & 4 \end{pmatrix}

    A+AT=(1+12+33+24+4)=(2558)A + A^T = \begin{pmatrix} 1+1 & 2+3 \\ 3+2 & 4+4 \end{pmatrix} = \begin{pmatrix} 2 & 5 \\ 5 & 8 \end{pmatrix}

    Note: A+ATA + A^T is always a symmetric matrix.

    Hence, Option A is correct.

    Latest Competitive Exams Update

    Latest Exam Notifications 2025

    Stay updated with all competitive exam notifications — SSC, Banking, Railways, UPSC and State PSC for 2025.

    April 2025

    Suggested Test Series

    More Matrices Questions