Question Video: Identifying a Matrix given Its Elements Order Mathematics • 10th Grade

Which of the following is the matrix 𝐴 = (𝑎_𝑖𝑗), where 𝑖 = 1 and 𝑗 = 1, 2? [A] 𝑎₁₁ and 𝑎₂₁ [B] 𝑎₁₂ and 𝑎₁₁ [C] (𝑎₁₁, 𝑎₁₂) [D] (𝑎₁₂, 𝑏₁₁)

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Video Transcript

Which of the following is the matrix 𝐴 equals 𝑎 𝑖𝑗, where 𝑖 equals one and 𝑗 equals one, two?

The first thing we can notice is that we’re multiplying 𝑖 and 𝑗. The set of 𝑖 is one, and the set of 𝑗 is one, two. Set 𝑖 is one by one, and set 𝑗 is one by two. This means that the solution matrix will be a one by two. Options a and b are two by ones; they don’t fit.

Now we have to look closely to see element order. 𝑗 is one and then two. That means the correct matrix will have the 𝑗 values in the order one, two. The correct matrix is 𝑎 one, one; 𝑎 one, two.