## anonymous 3 years ago Give the exact value of the expression without using a calculator: sin(2cos(inv) 1/5)

• This Question is Open
1. anonymous

idk

2. anonymous

let cos(inv) 1/5 = A

3. anonymous

$\sin (2A)= 2sinAcosA$

4. anonymous

what is A you substitute

5. anonymous

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

6. anonymous

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

7. anonymous

can you go on from here