How do you evaluate $sin ( arccos (15/17))$ ?

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Answer 1 · 2016-05-07T14:59:15

$sin x = +- 8/17.$

Call x the arc whose $cos x = 15/17.$
Find sin x.
$sin^2 x = 1 - cos^2 x = 1 - 225/289 = 64/289.$
$sin x = +- 8/17.$

How do you evaluate sin ( arccos (15/17)) sin ( arccos (15/17))?