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# Unit Vector: Unit Vector with Unknown Coordinates in All Entries

LINALG-YI4CYE

For which real numbers $x$ is $\begin{bmatrix} x \\\ 2x \\\ 3x \end{bmatrix}$ a unit vector?

Select ALL that apply.

A

$\pm\dfrac{1}{14}$

B

$\pm\dfrac{1}{7}$

C

$\pm\dfrac{1}{2}$

D

$\pm\dfrac{1}{\sqrt{14}}$

E

$\pm\dfrac{1}{\sqrt{7}}$

F

$\pm\dfrac{1}{\sqrt{7}}$