## William812 one year ago Give the exact value of the expression without using a calculator: sin(2cos(inv) 1/5)

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1. AKANicole

idk

2. telijahmed

let cos(inv) 1/5 = A

3. telijahmed

$\sin (2A)= 2sinAcosA$

4. telijahmed

what is A you substitute

5. telijahmed

$2\sin (\cos ^{-1}1/5) \cos (\cos ^{-1}1/5)$

6. telijahmed

$2\sin (\cos ^{-1}1/5) * 1/5$

7. telijahmed

can you go on from here