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Math Help - Referencce Angle

  1. #1
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    Smile Referencce Angle

    I was wondering what the reference angle is for:


    theta=3 (no degrees, so I am assuming it is in radians)

    Here is what I did:

    LIke I said I am assuming that the 3 is in radians

    If I'm not mistaken a reference angle is how far away an angle is from the nearest X-axis so with that being said here is how I went about buisness:

    180*3=540 degrees

    90+90+90+90+90+90=540 degrees

    On the first revolution of the unit circle it would land on the 180 degree mark

    Now as you can see this angle lands directly on top of the 540 because it is 540

    540=540

    I have tried various answers such as 0,-1, pi, -pi and the computer system still won't bite. Any suggetions?
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  2. #2
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by qbkr21 View Post
    180*3=540 degrees
    Your formula isn't correct. \pi rad = 180 degrees. So:

    \frac{3 \, rad}{1} \times \frac{180 \, degrees}{\pi \, rad} = \frac{540}{\pi} degrees  \approx 171.887338539 degrees

    So the reference angle is 180 - 171.887338539 = 8.112661461 degrees.

    -Dan
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  3. #3
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    Re:

    To be honest with you I know you multiply by (180/pi) however I am not looking for the measure in decimals, I could have done that, I am looking for it in terms of pi
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  4. #4
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by qbkr21 View Post
    To be honest with you I know you multiply by (180/pi) however I am not looking for the measure in decimals, I could have done that, I am looking for it in terms of pi
    Then leave the angle in radians.

    \frac{\pi}{2} < 3 < \pi

    So the reference angle will be \pi - 3 rad.

    -Dan
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  5. #5
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    Re:

    Thanks sir it worked. OK I see how you got it now...
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