Verified Solution • 2025–26 Session moderate

QJEEM25Mafffa: JEE Main 2025 Mathematics - Class 12 JEEM25Mafffa Solution: Let be a matrix such that and , then equals :

Let A=[aij]A=\left[a_{i j}\right] be a 3×33 \times 3 matrix such that A[010]=[001],A[413]=[010]A\left[\begin{array}{l}0 \\ 1 \\ 0\end{array}\right]=\left[\begin{array}{l}0 \\ 0 \\ 1\end{array}\right], A\left[\begin{array}{l}4 \\ 1 \\ 3\end{array}\right]=\left[\begin{array}{l}0 \\ 1 \\ 0\end{array}\right] and A[212]=[100]A\left[\begin{array}{l}2 \\ 1 \\ 2\end{array}\right]=\left[\begin{array}{l}1 \\ 0 \\ 0\end{array}\right] , then a23a_{23} equals :

Multiple Choice Options

  • A 2
  • B −- 1
  • C 1
  • D 0

Step-by-Step Verified Solution

amp; Let A=[a11amp;a12amp;a13a21amp;a22amp;a23a31amp;a32amp;a33]amp;A[010]=[001]⇒[a12a22a32]=[010]⇒a22=0;a12=0a32=1\begin{aligned}& \text { Let } A=\left[\begin{array}{lll}a_{11} & a_{12} & a_{13} \\a_{21} & a_{22} & a_{23} \\a_{31} & a_{32} & a_{33}\end{array}\right] \\& A\left[\begin{array}{l}0 \\1 \\0\end{array}\right]=\left[\begin{array}{l}0 \\0 \\1\end{array}\right] \Rightarrow\left[\begin{array}{l}a_{12} \\a_{22} \\a_{32}\end{array}\right]=\left[\begin{array}{l}0 \\1 \\0\end{array}\right] \Rightarrow \begin{array}{l}a_{22}=0 ; a_{12}=0 \\a_{32}=1\end{array}\end{aligned}

A[413]=[010]⇒4a11+a12+3a13=04a21+a22+3a23=1⇒4a21+3a23=14a31+a32+3a33=0A[212]=[100]⇒2a11+a12+2a13=12a21+a22+2a23=0⇒a21+a23=02a31+a32+2a33=0−4a23+3a23=1⇒a23=−1\begin{aligned}A\left[\begin{array}{l}4 \\1 \\3\end{array}\right]=\left[\begin{array}{l}0 \\1 \\0\end{array}\right] \Rightarrow \begin{array}{l}4 a_{11}+a_{12}+3 a_{13}=0 \\4 a_{21}+a_{22}+3 a_{23}=1 \Rightarrow 4 a_{21}+3 a_{23}=1 \\4 a_{31}+a_{32}+3 a_{33}=0\end{array} \\A\left[\begin{array}{l}2 \\1 \\2\end{array}\right]=\left[\begin{array}{l}1 \\0 \\0\end{array}\right] \Rightarrow \begin{array}{l}2 a_{11}+a_{12}+2 a_{13}=1 \\2 a_{21}+a_{22}+2 a_{23}=0 \Rightarrow a_{21}+a_{23}=0 \\2 a_{31}+a_{32}+2 a_{33}=0\end{array} \\-4 a_{23}+3 a_{23}=1 \Rightarrow a_{23}=-1\end{aligned}

Related Learning Resources & Exam Preparation