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anonymous

  • 5 years ago

Find the exact value of the given expression using a sum or difference formula. 1) sin345° 2) cos(11π)/12

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  1. anonymous
    • 5 years ago
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    1) sin(345) = sin(300+45)=sin(300)cos(45)+cos(300)sin(45)=(-sqrt(3)*sqrt(2))/(2*2) + (1*sqrt(2))/(2*2)=(-sqrt(6) + sqrt(2))/4

  2. anonymous
    • 5 years ago
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    2) cos(11pi/12)=cos (2π/3 + π/4) = cos 2π/3 cos π/4 - sin 2π/3 sin π/4 =-½*(√(2)/2) - √(3)/2* (√(2)/2) = (-sqrt(2)-sqrt(6))/4

  3. anonymous
    • 5 years ago
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    OK so I'm a little confused because my answer choices for #1 are: a.(√(3)+1)/(2√(2)) b.(√(3)-1)/(2√(2)) c.(-√(3)+1)/(2√(2)) d.(-√(3)-1)/(2√(2))

  4. anonymous
    • 5 years ago
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    Just factor out a sqrt(2) from my answer, and you should be able to find the right choice. :D

  5. anonymous
    • 5 years ago
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    oh ok thanks

  6. anonymous
    • 5 years ago
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    so it would be c then right?

  7. anonymous
    • 5 years ago
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    yes

  8. anonymous
    • 5 years ago
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    sweet! Gracias Senor!

  9. anonymous
    • 5 years ago
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    No problem. I'd appreciate it if you fanned me. :D

  10. anonymous
    • 5 years ago
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    Sure can do! Now your answer with three out of the same choice of answers doesn't match up though.. I don't think....

  11. anonymous
    • 5 years ago
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    I mean with number 2....

  12. anonymous
    • 5 years ago
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    What are your choices?

  13. anonymous
    • 5 years ago
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    same as the choices for #1...

  14. anonymous
    • 5 years ago
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    Factor out a sqrt(2). The answer would be d.

  15. anonymous
    • 5 years ago
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    Ohhhh I gotcha now lol sorry about that

  16. anonymous
    • 5 years ago
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    Haha np.

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