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Math Help - Vectors problem/check

  1. #1
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    Vectors problem/check

    Vectors d and e are such that |d| = 3 and |e| = 5 and the angle between them is 30 degrees. Determine |d - e|.

    I set it up like this:



    And did |d-e| = \sqrt{9+25-2(3)(5)(cos30)} = 8.02

    However the answer in the book is 2.83. Can anyone tell me where I'm going wrong or if it's a typo? Thanks!
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  2. #2
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    Quote Originally Posted by IanCarney View Post
    Vectors d and e are such that |d| = 3 and |e| = 5 and the angle between them is 30 degrees. Determine |d - e|.
    And did |d-e| = \sqrt{9+25-2(3)(5)(cos30)} = 8.02
    However the answer in the book is 2.83. Can anyone tell me where I'm going wrong or if it's a typo? Thanks!
    I cannot see how you got that.
    From the given the correct answer is \sqrt{8.019}.
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  3. #3
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    Quote Originally Posted by Plato View Post
    I cannot see how you got that.
    From the given the correct answer is \sqrt{19}.
    So the textbook is wrong.
    How did you get \sqrt{19}
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  4. #4
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    That is a typo. See my correction.
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  5. #5
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    Quote Originally Posted by Plato View Post
    That is a typo. See my correction.
    Ah, thanks!
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