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AFleming42

Find the exact value by using a half-angle identity. cos (5π/12) I have no clue how to do this....

  • one year ago
  • one year ago

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  1. emhart2012
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    the formula is cos=+or- 1+cos/2 all over a square root

    • one year ago
  2. emhart2012
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    so it will be…. 1 + cos(5pi/12)/2 all under a square root

    • one year ago
  3. Lukecrayonz
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    @jim_thompson5910

    • one year ago
  4. Lukecrayonz
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    @timo86m

    • one year ago
  5. AFleming42
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    that makes absolutely no sense to me...

    • one year ago
  6. Lukecrayonz
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    @AccessDenied

    • one year ago
  7. AFleming42
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    is that the final answer?

    • one year ago
  8. emhart2012
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    no you need to solve it on you calculator

    • one year ago
  9. AFleming42
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    ehhh I have an example problem for sin and the answer isn't an exact value and there's a heck of a lot more steps

    • one year ago
  10. jim_thompson5910
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    cos (5pi/12) = cos ((1/2)*(5pi/6)) cos (5pi/12) = sqrt( (1+cos(5pi/6))/2 ) cos (5pi/12) = sqrt( (1-sqrt(3)/2)/2 ) cos (5pi/12) = sqrt( 1/2-sqrt(3)/4 ) cos (5pi/12) = sqrt( (2-sqrt(3))/4 ) cos (5pi/12) = sqrt(1/4)*sqrt( 2-sqrt(3) ) cos (5pi/12) = (1/2)*sqrt( 2-sqrt(3) )

    • one year ago
  11. AFleming42
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    Thank you @jim_thompson5910 (:

    • one year ago
  12. jim_thompson5910
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    yw

    • one year ago
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