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Construct a 2 ×3 matrix A = [aj j] whose elements aj j are given by: (i) ai j = i + j (ii) ai j = (i + j)2/2

(i) Given

\[{{a}_{i\text{ }j~}}=\text{ }i\text{ }+\text{ }j\]

Let

\[A\text{ }=\text{ }[a{{~}_{i\text{ }j}}]{{~}_{2\times 3}}\]

So, the elements in a \[2\text{ }\times \text{ }3\] matrix are

\[{{a}_{11}},\text{ }{{a}_{12}},\text{ }{{a}_{13}},\text{ }{{a}_{21}},\text{ }{{a}_{22}},\text{ }{{a}_{23}}\]

\[{{a}_{11}}~=\text{ }1\text{ }+\text{ }1\text{ }=\text{ }2\]

\[{{a}_{12}}~=\text{ }1\text{ }+\text{ }2\text{ }=\text{ }3\]

\[{{a}_{13}}~=\text{ }1\text{ }+\text{ }3\text{ }=\text{ }4\]

\[{{a}_{21}}~=\text{ }2\text{ }+\text{ }1\text{ }=\text{ }3\]

\[{{a}_{22}}~=\text{ }2\text{ }+\text{ }2\text{ }=\text{ }4\]

\[{{a}_{23}}~=\text{ }2\text{ }+\text{ }3\text{ }=\text{ }5\]

Substituting these values in matrix A we get,

(ii) Given

\[{{a}_{i\text{ }j}}~=\text{ }{{\left( i\text{ }+\text{ }j \right)}^{2}}/2\]

Let

\[A\text{ }=\text{ }{{[{{a}_{i\text{ }j}}]}_{2\times 3}}\]

So, the elements in a

\[2\text{ }\times \text{ }3\]

matrix are

\[{{a}_{11}},\text{ }{{a}_{12}},\text{ }{{a}_{13}},\text{ }{{a}_{21}},\text{ }{{a}_{22}},\text{ }{{a}_{23}}\]

Let

\[A\text{ }=\text{ }{{[{{a}_{i\text{ }j}}]}_{2\times 3}}\]

So, the elements in a

\[2\text{ }\times \text{ }3\]

matrix are

\[{{a}_{11}},\text{ }{{a}_{12}},\text{ }{{a}_{13}},\text{ }{{a}_{21}},\text{ }{{a}_{22}},\text{ }{{a}_{23}}\]

\[{{a}_{11}}~=\]

RD Sharma Solutions for Class 12 Maths Chapter 5 Image 13

\[{{a}_{12}}~=\]

\[{{a}_{13}}~=\]

\[{{a}_{21}}~=\]

\[{{a}_{22}}~=\]

\[{{a}_{23}}=\]

Substituting these values in matrix A we get,