SOLUTION: Use the formula in part c (sin(alpha+beta)=sin alpha*cos beta+cos alpha*sin beta)and the values for sin18 (1/4sqrt(5)+1) and cos18 (1/4sqrt(10+2sqrt(5)) to show that sin36=sqrt(10-

SOLUTION: Use the formula in part c (sin(alpha+beta)=sin alphacos beta+cos alphasin beta)and the values for sin18 (1/4sqrt(5)+1) and cos18 (1/4sqrt(10+2sqrt(5)) to show that sin36=sqrt(10-

Question 844009: Use the formula in part c (sin(alpha+beta)=sin alpha*cos beta+cos alpha*sin beta)and the values for sin18 (1/4sqrt(5)+1) and cos18 (1/4sqrt(10+2sqrt(5)) to show that sin36=sqrt(10-2sqrt(5)/4). Hint: The resulting algebra turns out to be much easier if you first find sin^2(36), simplify, and then take the square root.
I have no idea how to prove sin36! I've tried multiple times and it never works out. Please help!
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Use Google to search for "sin(36)" and you will
see a nice derivation of the solution you are
looking for.
Cheers,
Stan H.
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