## Linear Algebra and Its Applications, exercise 1.4.7

Exercise 1.4.7. Given the n-dimensional row vector y and column vector x, express their inner product in summation notation.

$yx = \begin{bmatrix} y_1&y_2&\cdots&y_n \end{bmatrix} \begin{bmatrix} x_1 \\ x_2 \\ \vdots \\ x_n \end{bmatrix} = y_1 x_1 + y_2 x_2 + \cdots + y_n x_n = \sum_{i = 1}^{i = n} y_i x_i$