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    This question has been annoying me for a while. I don't understand what I'm doing wrong. The answer is an integer between 0 and 999. The question is attached

    Firstly I did the Cos^-1 of 1/3 and then multiplied it by 2 to calculate angle c. Then I did 180 - angle C to get:

    38.94244127. Then I subtracted Pi and divided it by 2 to get 17.90042431.

    Then I put this into tan^2 and I got 0.1043285979, which is obviously not an integer.

    I can't figure out where I went wrong or if I'm missing something obvious.

    Please help :/

    On a side note, how do you make latex bigger?, I forgot.
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    You should be working in radians. The answer is a small integer.
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    (Original post by ThatPerson)
    This question has been annoying me for a while. I don't understand what I'm doing wrong. The answer is an integer between 0 and 999. The question is attached

    Firstly I did the Cos^-1 of 1/3 and then multiplied it by 2 to calculate angle c. Then I did 180 - angle C to get:

    38.94244127. Then I subtracted Pi and divided it by 2 to get 17.90042431.

    Then I put this into tan^2 and I got 0.1043285979, which is obviously not an integer.

    I can't figure out where I went wrong or if I'm missing something obvious.

    Please help :/

    On a side note, how do you make latex bigger?, I forgot.
    Why?
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    (Original post by electriic_ink)
    Why?
    It is a Triangle ABC. Triangles have total angles of 180 degrees, so once I calculated angleC, I subtracted it from 180 to get the sum of angleA plus angle B, which was needed for the next question.
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    (Original post by Mr M)
    You should be working in radians. The answer is a small integer.
    Is the answer 8?

    How do I know if I'm meant to be using radians?
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    (Original post by ThatPerson)
    Is the answer 8?

    How do I know if I'm meant to be using radians?
    Yes.

    Isn't the pi and the absence of the degree symbol a bit of a clue?
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    (Original post by Mr M)
    Yes.

    Isn't the pi and the absence of the degree symbol a bit of a clue?
    :dontknow: I've never worked in radians before, but I'll be sure to remember that.
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    (Original post by ThatPerson)
    :dontknow: I've never worked in radians before, but I'll be sure to remember that.
    Oh. Well now you are out of short trousers you will be using radians all the time.
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    (Original post by Mr M)
    Oh. Well now you are out of short trousers you will be using radians all the time.
    Well, I can wait till September at least.

    I'm still in short trousers.
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    (Original post by ThatPerson)
    Well, I can wait till September at least.

    I'm still in short trousers.
    You will soon learn that

    \cos x = \cos (-x)

    and

    \displaystyle \tan^2 x = \frac{1}{\cos^2 x} -1

    If you let \displaystyle x=\frac{-C}{2} then the result follows with no calculator required.

    You just need to calculate the reciprocal of the square of one third minus one.
 
 
 
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