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anonymous

  • one year ago

Us the Sum Formula to: a. Find the exact value of cos 105 degrees b. Find the exact value of sin 5pi/12

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  1. ganeshie8
    • one year ago
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    Hint for part a : 105 = 60 + 45

  2. anonymous
    • one year ago
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    @jim_thompson5910

  3. rvc
    • one year ago
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    cos(A+B)=?

  4. anonymous
    • one year ago
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    @rvc wait is that it?

  5. freckles
    • one year ago
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    the question already provides a hint use the sum formula and we know to use the sum formula for cosine since we are asked to find cos(105) and @ganeshie8 gave you the hint that 105 is 60+45 and @rvc is just trying to get you to look at your identitys sheet and copy over the identity mentioned for cos(A+B) and replace the A with 60 and the B with 45 and evaluate using unit circle

  6. anonymous
    • one year ago
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    how did he get 60 and 45 though? @freckles

  7. myininaya
    • one year ago
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    60 and 45 when added gives you 105

  8. anonymous
    • one year ago
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    yeah but why those in particular? 100 + 5 gives you 105 too?

  9. myininaya
    • one year ago
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    is 100 and 5 on the unit circle?

  10. myininaya
    • one year ago
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    60 and 45 are

  11. rvc
    • one year ago
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    well we have those values already and can easily plug in

  12. ganeshie8
    • one year ago
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    |dw:1433395044353:dw|

  13. anonymous
    • one year ago
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    OH OKAY

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