Answer
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Work Step by Step
Recall:
(1) An angle and its reference angle either have the same trigonometric function values or differ only in signs.
(2) $\tan{\theta} = \dfrac{y}{x}$
$\frac{3\pi}{2}$ is a special angle whose terminal side is the negative y-axis..
Note that the negative y-axis intersects the unit circle at the point $(0, -1)$.
Therefore,
$\tan{(\frac{3\pi}{2})}=\frac{-1}{0}$, which is undefined.