SOLUTION: Is this correct? simplifying cosine and sine equation? (a) Simplify: 20 sin 2θ cos 2θ = 20sin2(4θ) or is it 20sin(8θ)? (b) Simplify and then find the

Algebra ->  Trigonometry-basics -> SOLUTION: Is this correct? simplifying cosine and sine equation? (a) Simplify: 20 sin 2θ cos 2θ = 20sin2(4θ) or is it 20sin(8θ)? (b) Simplify and then find the      Log On


   

Question 925535: Is this correct? simplifying cosine and sine equation?
(a) Simplify: 20 sin 2θ cos 2θ =
20sin2(4θ) or is it 20sin(8θ)?


(b) Simplify and then find the value:
sin 13π/12 cos 13π/12=
What should I do here?

THANKS!
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
(a) Simplify: 20 sin 2θ cos 2θ =
20sin2(4θ) or is it 20sin(8θ)?
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since sin(2t) = 2sin(t)cos(t)
20*sin(2t)cos(2t) = 10*(2sin(2t)cos(2t)) = 10*sin(2(2t)) = 10sin(4t)
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(b) Simplify and then find the value:
sin 13π/12 cos 13π/12= (1/2)sin(2(13pi/12) = (1/2)sin(13pi/6)
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Cheers,
Stan H.
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