If matrix <

We are given that,

We need to compute AA^T.

We know that the transpose of a matrix is a new matrix whose rows are the columns of the original.

So, transpose of matrix A will be given as

Multiplying A by A^T,

In multiplication of matrices,

Dot multiply the matching members of 1^st row of first matrix and 1^st column of second matrix and then sum up.

(a₁₁ a₁₂ a₁₃)(b₁₁ b₂₁ b₃₁) = a₁₁ × b₁₁ + a₁₂ × b₂₁ + a₁₃ × b₃₁

So,

(1 2 3)(1 2 3) = 1 × 1 + 2 × 2 + 3 × 3

⇒ (1 2 3)(1 2 3) = 1 + 4 + 9

⇒ (1 2 3)(1 2 3) = 14

Thus,