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anonymous

  • one year ago

use the law of cosines to find the value of 2⋅3⋅4 cosθ

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  1. anonymous
    • one year ago
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    @dan815

  2. anonymous
    • one year ago
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    @taramgrant0543664

  3. anonymous
    • one year ago
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    what do you mean by 2⋅3⋅4 cosθ You mean \[\cos 2\theta\quad,\cos3\theta,\quad \cos3\theta\]?

  4. taramgrant0543664
    • one year ago
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    Do you have a triangle that corresponds to this question?

  5. anonymous
    • one year ago
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    |dw:1438361201942:dw|

  6. taramgrant0543664
    • one year ago
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    This is the law c^2=A^2+b^2−2abcosC

  7. anonymous
    • one year ago
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    21

  8. taramgrant0543664
    • one year ago
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    4=16+9-2(4)(3)cosC 21=24cosC 0.875=cosC C= 28.96

  9. anonymous
    • one year ago
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    A. 24 B. 21 C. -24 D. -21

  10. taramgrant0543664
    • one year ago
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    I just understood the whole 2,3,4 thing and ya it is equal to 21 I just assume you had to solve for the angle

  11. anonymous
    • one year ago
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    so is it 21 then

  12. taramgrant0543664
    • one year ago
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    Yes it is

  13. anonymous
    • one year ago
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    thanks

  14. anonymous
    • one year ago
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    can you help me with another question please? @taramgrant0543664

  15. taramgrant0543664
    • one year ago
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    I can try!

  16. anonymous
    • one year ago
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    ok

  17. anonymous
    • one year ago
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    |dw:1438362470160:dw|

  18. anonymous
    • one year ago
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    true or false

  19. anonymous
    • one year ago
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    @taramgrant0543664

  20. anonymous
    • one year ago
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    nvm

  21. anonymous
    • one year ago
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    wrong problem

  22. anonymous
    • one year ago
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    Suppose a triangle has sides a, b, and c, and that a2 + b2 > c2. Let be the measure of the angle opposite the side of length c. Which of the following must be true? Check all that apply.

  23. anonymous
    • one year ago
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    A. cos < 0 B. cos > 0 C. is an acute angle. D. The triangle in question is a right triangle.

  24. anonymous
    • one year ago
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    @taramgrant0543664

  25. taramgrant0543664
    • one year ago
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    I'd like to think it would be D but I'm not certain

  26. anonymous
    • one year ago
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    its more than 1 answer

  27. anonymous
    • one year ago
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    i think its a and d

  28. anonymous
    • one year ago
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    what do you think

  29. taramgrant0543664
    • one year ago
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    A and D that's what I'm thinking

  30. anonymous
    • one year ago
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    yup yup

  31. anonymous
    • one year ago
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    Suppose a triangle has sides a, b, and c, and the angle opposite the side of length b is obtuse. What must be true?

  32. anonymous
    • one year ago
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    how about this one

  33. anonymous
    • one year ago
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    A. b2 + c2 < a2 B. a2 + c2 > b2 C. a2 + c2 < b2 D. a2 + b2 < c2

  34. anonymous
    • one year ago
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    @taramgrant0543664

  35. anonymous
    • one year ago
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    i think it a @taramgrant0543664

  36. taramgrant0543664
    • one year ago
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    Ya I was trying to think it out and I was thinking it was A but I was testing out the other options too to double check

  37. anonymous
    • one year ago
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    that good

  38. anonymous
    • one year ago
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    it wasnt a

  39. anonymous
    • one year ago
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    its aight

  40. phi
    • one year ago
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    Suppose a triangle has sides a, b, and c, and the angle opposite the side of length b is obtuse. What must be true? they tell you about angle B (opposite side b) is bigger than 90 degrees (i.e. obtuse) I would write down the law of cosines in the form that uses angle B (because that is the angle we know about) b^2 = a^2 + c^2 - 2 a c cos B next, we (should!) know cos of an angle bigger than 90 (but less than 180) is negative in other words - 2 ac cos B will turn into a positive number (because -2 * neg cos will be positive) in other words, we can say b^2 = a^2 + c^2 + more if we subtract off more from the right side, the right side will no longer be equal to the left side ... it will be too small. we can say b^2 > a^2 + c^2 or (means the same thing) a^2 + c^2 < b^2

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