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Math Help - missing angle

  1. #1
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    missing angle

    hi, can you check if im right when trying to find the missing angle of this shape?

    missing angle-shape.jpg

    to work this out i did this:

    inverse tan 7/11= 7.44???

    is this correct? if not where am i going wrong?

    thanks!
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  2. #2
    Senior Member BAdhi's Avatar
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    how did you calculate tan^{-1}(7/11) (and state whether radians or degrees)
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  3. #3
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    on my calculator i just wrote " tan^-1 7/11= 7.44

    my calculator is in degrees!
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  4. #4
    A Plied Mathematician
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    Your calculator, due to the lack of parentheses, computed \tan^{-1}(7)/11, not \tan^{-1}(7/11). Try that again, and see what you get. This is what BAdhi was getting at, I think. Incidentally, you were right to doubt the correctness of the result. You should always have a rough idea of what a calculator is going to give you.
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  5. #5
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    okay, so i nned to do \tan^{-1}(7)/11, = 32.47??
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  6. #6
    A Plied Mathematician
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    Right answer, wrong typing. You should have

    \tan^{-1}(7/11)\approx 32.47^{\circ}.
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  7. #7
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    e^(i*pi)'s Avatar
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    Some models require the argument first. If this is the case type 7 \div 11 and then inverse tan button
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