How do you evaluate $Sin(Arctan 3)$ ?

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Answer 1 · 2016-05-14T17:00:49

$+-3/sqrt 10=+-0.9487$ , nearly.

Let a = arc tan 3. Then tan a = 3 > 0.

So, a is in either 1st quadrant or in the 3rd.

Accordingly, the given expression $sin a = +-3/sqrt 10$

How do you evaluate Sin(Arctan 3)Sin(Arctan 3)?