Let $A = [a_{ij}]_{3×3}$ be a matrix, defined by $a_{ij}=\left\{\begin{matrix}2i+3j,&i<j\\6,&i=j\\3i-2j,&i>j\end{matrix}\right.$. The number of elements in A which are greater than 6, is |
6 5 4 3 |
4 |
The correct answer is Option (3) → 4 Matrix is defined as: $a_{ij}=\begin{cases}
2i+3j , & i For $3\times 3$ matrix: $A=\begin{bmatrix} a_{11} & a_{12} & a_{13} \\ a_{21} & a_{22} & a_{23} \\ a_{31} & a_{32} & a_{33} \end{bmatrix}$ Now, compute each element: $a_{11}=6$ $a_{12}=2(1)+3(2)=2+6=8$ $a_{13}=2(1)+3(3)=2+9=11$ $a_{21}=3(2)-2(1)=6-2=4$ $a_{22}=6$ $a_{23}=2(2)+3(3)=4+9=13$ $a_{31}=3(3)-2(1)=9-2=7$ $a_{32}=3(3)-2(2)=9-4=5$ $a_{33}=6$ So, $A=\begin{bmatrix} 6 & 8 & 11 \\ 4 & 6 & 13 \\ 7 & 5 & 6 \end{bmatrix}$ Elements greater than 6 are: $8, 11, 13, 7$ Number of such elements = $4$ |