$\"\"$

Consider the dot product $\"\"$ .

The result of $\"\"$ is $\"\"$ , where $\"\"$ is a scalar value.

Consider $\"\"$ .

Substitute $\"\"$ in the above expression.

$\"\"$

Since $\"\"$ is a scalar value, and $\"\"$ is a vector value, $\"\"$ .

Thus, Ethan is correct.

$\"\"$

Ethan is correct.